Today is the moment we've all been waiting for: Election Day.

Okay, maybe that's not true. Voter enthusiasm is notably low, especially among Democrats. Turnout is likely to be far lower than 2012. Unlike 2010, when a wave of conservative anger washed away Democrats' control of the House and their supermajority in the Senate, there's no obvious story of this election. It's hard to remember an election when there seemed to be no single cause animating the electorate.

But that doesn't mean the election doesn't matter—far from it. The obvious focus is on the Senate, where Republicans are widely expected to win control from Democrats. Leading prognosticators put the chance at GOP control anywhere from 63 percent to a whopping 96 percent. So the factor to watch is probably less who controls the Senate than how many seats Republicans can take.

It's not a slam dunk, as those probabilities show. There are 36 Senate elections, including three special elections, but only 10 races are competitive. The GOP needs to win five of those seats to gain control (to net a total of six), and Republican candidates lead the polls in seven of the 10, according to averages on RealClearPolitics. Two of the 10 are currently Republican held.

Some of those races are extremely tight; in some states, notably Alaska, reliable polling is difficult and it's hard to know how much stock to put in pre-election surveys. On Monday, key Democrats—including Vice President Biden and White House Press Secretary Josh Earnest—predicted the party would cling to control, perhaps because that's a better political strategy than throwing in the towel early. Democrats' last-ditch hope is for a sophisticated get-out-the-vote operation to drive turnout among unlikely voters, surprising Republicans much as President Obama did in his 2012 reelection. In some cases, early voting has fed that hope, but there are also signs turnout won't rescue sinking candidates. (See below for a rundown of competitive Senate races.)

There's a good chance we won't know the final count in the Senate Tuesday night—or possibly until after the rest of the new Congress is seated. Barring unexpectedly strong showings from the candidates, races in Louisiana and Georgia seem likely to head to runoff elections, in December and January, respectively. Depending on how other races shake out, one of those runoffs could potentially determine control of the Senate, though the odds are increasingly remote as Republicans pull away.

There's less drama in the House, where Republicans are all but certain to retain control and, in fact, gain seats. The GOP continues to benefit from redistricting plans drawn up after the 2010 elections, which favor Republican candidates, while Democrats have struggled to gain any traction at all. Predictions for Republican gains range from around six to 12 seats. The reason that number isn't larger is that the GOP already dominates the chamber, especially following its strong performance in the 2010 midterm elections; it has nearly maxed out the number of seats it can gain under current political conditions.

The only bleak spot on the board for Republicans—and the brightest spot for Democrats—is gubernatorial races, where Democrats are expected to pick up seats. That movement is driven in part by the GOP's success in 2010; this year, Republican governors who won then are defending seats in states that lean more Democratic. The most dramatic case is in Wisconsin, where Governor Scott Walker faces his third election in four years, including a failed recall attempt in 2012. If Walker holds on to win, he is expected to vie for the 2016 Republican nomination, while a loss would likely end that quest.

In the absence of a single major issue, the biggest issue in many races has been someone who's not on any ballot: Barack Obama, who has proven to be a millstone around Democrats' necks, such that few of them have wanted him to campaign for them. Presidents' parties usually lose seats in midterm years, especially in the sixth year. The president's approval rating is a good indicator of how his party will fare, and Obama's is low. And many Democrats are running in states—from Alaska to Kentucky—where Obama is especially unpopular.

Regardless of how this all shakes out, there's an overwhelming sense that the next two years are likely to see more of the same gridlock. The first two years of Obama's second term have seen little movement on much of anything—the highlights, such as they are, included a government shutdown, the disastrous initial rollout of the Affordable Care Act, and a succession of foreign crises. In some ways, it's hard to imagine much less getting done in Washington than is already happening.

But here are two ways that conventional wisdom could be very wrong. First, things could get even more jammed up. Take presidential appointees. So far, 280 Obama appointees have been confirmed to federal courts. Some of those confirmations came only after Senate Democrats changed the rules to lower the threshold for confirmation to 50 votes—a move that, in turn, stemmed from unprecedented obstruction by Senate Republicans. The administration also has to staff various executive jobs, including Attorney General Eric Holder's replacement. It's easy to imagine that a GOP-controlled Senate would be a place for Obama appointments to go to die. On the other hand, some Republicans—especially moderates—see the next two years as a chance to move real legislation, to force Obama to agree to a set of compromises palatable to moderates in both parties.

Republican control of Congress could provide the stage for the next phase of the civil war in the GOP, with both wings jockeying for position ahead of the 2016 presidential election. Establishment and moderate figures like Senator Rob Portman want to improve the party's image—which, despite their projected success, remains awful—through constructive work. Hardliners like Representative Steve King and Senator Ted Cruz want to lay down a marker for an uncompromising conservatism, which they think will set the party up for victory in the presidential race, by obstructing any progress and investigating the administration. Many Democrats, as it happens, hope for the same thing. As their chances to hold on in the Senate have dimmed, many liberals' new fond hope is that Republicans will overreach and turn off voters, setting up a Democrat sweep of the White House, Senate, and perhaps even the House—an echo of what happened in 2012, following the GOP victories in 2010.

Assuming all goes as expected and Republicans take the Senate and gain ground in the House, any claim to a mandate will ring somewhat hollow. The party's favorability ratings are atrocious, and as low as Obama's approval has sunk, it is still nearly four times as high as Congress's ratings. Moreover, the results will in large part display an emerging dynamic in which the group of people who vote in midterm and presidential elections are vastly different. Midterm turnout has of course always been lower than that of presidential races, but in recent years a division between the two has become more apparent. Rather than offering a microcosm of presidential voters, midterm voters are older, whiter, and more conservative. Since 2008, that has created a see-saw effect: Democrats win in presidential years, Republicans claw back with gains in Congress in off years. That pattern, should it hold, bodes ill for either party's agenda—and for the republic.

The polls begin closing at 7 p.m. on the East Coast, and we'll have full coverage on The Atlantic.

Senate Races to Watch

Alaska: Incumbent Democrat Mark Begich, a one-term senator, is on the ropes against Republican Dan Sullivan, trailing in almost every recent poll. But the numbers are close, and polling in Alaska is notoriously unreliable. Begich has tried to wring votes out of unusual constituencies like remote Native Alaskans, but it may not save him.

Arkansas: Mark Pryor is another Democratic incumbent in a tight spot. The good news for the two-term senator is that he has run unexpectedly well against Representative Tom Cotton, a highly touted GOP recruit. The bad news is that he has long been expected to lose, and the race seems to have finally settled out, with Cotton holding high-single-digit leads in recent polls.

Colorado: Colorado has trended blue in recent years, but it has turned into an unexpected nightmare for Democrats in 2014. Republican Representative Cory Gardner has run a surprisingly effective campaign as one-term incumbent Mark Udall flails. Democrats insist that pollsters consistently underestimate the Hispanic vote in the Rocky Mountain State, and they'd better hope that's true.

Georgia: Don't expect to know the outcome of this race any time soon. Democrats see Georgia as the beachhead for a comeback in the South, and Michelle Nunn—daughter of longtime centrist Senator Sam Nunn—carries many of those hopes in her race against David Perdue. The Republican, a first-time candidate, has been somewhat gaffe-prone, but he's kept a small lead. If neither candidate gets 50 percent of the vote, there will be a runoff January 6—incredibly, after the rest of the new Congress is seated—that would likely favor the GOP.

Iowa: The Hawkeye State is another bad dream for Democrats, who thought they had a strong candidate to replace retiring Democrat Tom Harkin in Representative Bruce Braley; meanwhile, several sought-after Republicans passed on the race, and Joni Ernst won the nomination in a last-minute sprint. Since then, Ernst has been a campaign dynamo and set aside radical prior statements, while Braley has been listless and prone to missteps and scandals. This race seems to have slipped away from the Democrats.

Kansas: In one of the weirder races of this election, long-time Republican Senator Pat Roberts is close to losing to independent Greg Orman, a first-time candidate who won't say for certain with whom he'll caucus. Roberts has struggled to even claim he lives in Kansas, while Democrats withdrew their candidate and have thrown their support to Orman.

Kentucky: If Democrats win, it'll be the race of the cycle—if. But while Democrat Alison Lundergan Grimes has proved a formidable campaigner, it looks like longtime Senator Mitch McConnell will win reelection and ascend to the post of Senate majority leader. Grimes has kept the race close, but no model gives her more than a small chance at an upset.

Louisiana: The other good shot at a runoff is in Louisiana, where Democrat Mary Landrieu is trying to fend off challenges to her seat from Representative Bill Cassidy and Rob Maness, two Republicans. No candidate seems likely to win an outright majority, setting up a December runoff between the top two candidates, which would seem to favor Cassidy.

New Hampshire: Can Scott Brown make magic happen twice—in two different states? In January 2010, he won a special election for Ted Kennedy's old seat in Massachusetts; lost it to Elizabeth Warren in 2012; then moved to New Hampshire and announced he'd challenge Democratic Senator Jeanne Shaheen. Brown's campaign long seemed hapless and listless, but he's closed the gap in the final weeks. Shaheen seems to have a slight edge, but the race is close.

North Carolina: This is a good race to watch early today. If Republican Thom Tillis wins the state, Democratic chances at holding the Senate shrink to virtually nothing. But Senator Kay Hagan has run a tight campaign and has a slight edge in most polls against Tillis, who has struggled against the unpopularity of the GOP-controlled state legislature in which he is a leader.

Gubernatorial Races to Watch

Alaska: This is another head-scratcher. Incumbent Republican Sean Parnell has fallen behind in polls to a fusion ticket of independent Bill Walker, running with a Democratic lieutenant-governor candidate. Walker even won the endorsement of Sarah Palin—whom Parnell once served as lieutenant governor. Prior caveats about Alaska polling apply.

Colorado: John Hickenlooper ran for office as a different kind of Democrat—a relentlessly positive former businessman and moderate. But he's found himself taking a series of liberal stands that have endangered him against Republican Bob Beauprez. Hickenlooper has maintained a tiny but consistent lead; his fortunes could be tied to Senator Mark Udall.

Connecticut: Even in a consistently blue state, Democrat Dan Malloy has struggled against Republican Tom Foley in a 2010 rematch. That race was extremely close, and this one promises to be as well.

Florida: The question for many Florida voters seems to be not which candidate they like more, but which they hate more. Republican Rick Scott is one of the least-liked governors in the nation, but he's facing off against Charlie Crist, who was already governor—as a Republican—and is often derided as an unprincipled opportunist. Crist has held a small lead in recent polls.

Georgia: In the undercard of Democrats' dynastic push in the Peach State, Jason Carter—grandson of former President Jimmy—is trying to unseat Governor Nathan Deal. Deal has been shaky, but looks likely to hold on.

Illinois: Governor Pat Quinn could pull off one of the most remarkable recoveries in recent memory today. Quinn probably shouldn't have even made it out of a Democratic primary, and he entered the general-election race against Bruce Rauner—a wealthy businessman—as the underdog. In the final weeks of the campaign, Quinn has nosed out ahead of a vulnerable Rauner in a blue state.

Kansas: In addition to the wacky Senate race between Pat Roberts and Greg Orman, Kansas has a fascinating gubernatorial race. Republican Sam Brownback, a former senator, seems to have overreached with a staunch conservative program. In response, the state's moderate Republicans banded together with Democrats to back state Representative Paul Davis. If the polling is right, Brownback will lose stunningly.

Massachusetts: As if it's not bad enough that Scott Brown could knock out a Democratic senator in New Hampshire, the candidate he beat in 2010—Attorney General Martha Coakley—seems to be about on the verge of blowing another race, this one for governor against Republican Charlie Baker. Sure, it's the deep-blue Bay State, but Baker is a moderate who even won the Boston Globe endorsement, while Coakley has proved to be ... well, Martha Coakley.

Maine: Paul LePage might be America's most ridiculous governor—no small feat—and isn't popular with Mainers. So why is this race close? LePage, a Republican, only won in 2010 because Democrats split between independent Eliot Cutler and Democrat Libby Mitchell; Cutler finished less than 10,00 votes back. This time, he's running again, alongside Democratic Representative Mike Michaud. Last week, Cutler gave his blessing to supporters to strategically vote for Michaud, i.e., against LePage.

Michigan: Incumbent Republican Rick Snyder seemed to have the inside track on this election, but Democrat Mark Schauer quietly snuck up on him, and Snyder seemed slow to strike back. The governor is still favored to win, but he only leads by a couple of points in recent polls.

Wisconsin: It's last alphabetically, but this could be the most consequential of the governors' races. Scott Walker has emerged as a national Republican force and likely 2016 presidential candidate. But that path could be closed off if he can't win reelection. Walker is in a tight race against Democrat Mary Burke, leading by low single digits in recent polls. But he's no stranger to tough campaigns, having beaten back the 2012 recall election, and winning would reinforce his national brand.