Alaska GOP Gov. Sean Parnell is locked in a late-breaking, competitive challenge to retain the governor's mansion—but you wouldn't know it from the airwaves in Anchorage or Fairbanks, where he barely has a presence.

That's because the Senate race between Democratic Sen. Mark Begich and GOP challenger Dan Sullivan has eclipsed everything else in Alaska. More than 50,000 Senate ads had aired there by mid-October, compared with a paltry 170 spots for Parnell for the entire cycle. For Parnell and his allies, like the Republican Governors Association, there's almost no ad inventory left to buy (or it comes only at exorbitant rates).

Governors' races may technically be the top of the ticket, but it's the Senate races that are the real top tier of 2014.

And this year, governor's races in a half-dozen states are largely at the mercy of the competitive Senate races there—as well as all the ad money, field operations, and national messaging they bring with them.

In many places, gubernatorial races are getting drowned out on the airwaves by an unprecedented amount of midterm super PAC money; other gubernatorial hopefuls are being bolstered by the robust field operations in place to help Senate candidates or incumbents. The dynamic cuts across party lines: Democrats and Republicans are both being helped and hurt by their Senate counterparts in races across the country.

What's more, many of the gubernatorial races in question were far from top-tier when the 2014 election cycle began: No one expected Kansas or Alaska, for example, could possibly be toss-up races in the final weeks before Election Day. But the combination of unique circumstances and immense Senate resources has put several of these races on the map.

Alaska, for example, became a race when Democratic candidate Byron Mallott dropped out and joined a "unity ticket" with independent candidate Bill Walker. The race, which originally would have been a breeze for Parnell in deep-red Alaska, suddenly became a toss-up. (Sarah Palin, the former Alaska governor, endorsed Walker and Mallett over her former GOP colleague this week.) Parnell may not be filling up much airtime on his own, but Republicans hope that ad efforts on behalf of Sullivan's Senate bid could end up bolstering Parnell as well.

The race for governor of Colorado is following a similar path. Bob Beauprez, the GOP candidate, has trailed by millions in fundraising, making it tough for him to keep pace with incumbent Democratic Gov. John Hickenlooper. Add to that the fact that contribution limits are capped at $1,100 for gubernatorial candidates, and it puts Beauprez at a major disadvantage. According to the Wesleyan Media Project, pro-Hickenlooper ads ran more than three times as often as pro-Beauprez ads from Sept. 26 to Oct. 9—that's 2,115 for Hickenlooper and just 646 for Beauprez.

Enter the Senate race between incumbent Democratic Sen. Mark Udall and Republican Rep. Cory Gardner, which has already brought at least an estimated $40 million in ad money into the state. A total of 43,412 Senate ads had run in the race as of Oct. 9, with many more to come before Election Day. Though the issues in the Senate race and gubernatorial race are different—Hickenlooper's problems have more to do with his decisions on state issues than the national environment, while it's the opposite for Udall—Republicans do think a strong victory by Gardner in the Senate race could help pull Beauprez over the finish line.

Recent polling finds Beauprez running several points behind Gardner statewide: Gardner is up 4 points in the RealClearPolitics average of latest polls, while Hickenlooper leads Beauprez by a tiny 0.2 percentage-point margin, effectively a tie.

While the airwaves may be giving Beauprez a boost, observers say Hickenlooper benefits from the competitive Senate race too—in terms of the huge Democratic ground operation. The national Democratic turnout program is called the Bannock Street Project, named for Colorado Sen. Michael Bennet's field operation in 2010; as a result, it's stronger in Colorado than almost anywhere else on the map.

"John Hickenlooper, because he's a moderate, center-left guy, there's not much passion for him," said independent Colorado-based pollster Floyd Ciruli. "So if any minorities and young people and others are going to turn out and vote for him, they're only going to get there because the Democratic Party has this huge machine to save Mr. Udall."

That's true in Arkansas as well, where Democrats are pulling out all the stops to save incumbent Sen. Mark Pryor—and, by extension, the rest of the Democratic ticket. Former President Clinton has twice headlined rallies for Pryor as well as gubernatorial candidate Mike Ross.

Still, it's been tough for those gubernatorial hopefuls to make their own mark on the airwaves when they're totally blanketed by Senate ads.

"It's been difficult [for Ross and GOP candidate Asa Hutchinson] to get traction "¦ $40 million has been spent in the Senate race, so it's really difficult for the gubernatorial candidates to be heard through that," said Jay Barth, a professor at Hendrix College who works with the college's polling outfit. (The latest Talk Business/Hendrix poll gave both Hutchinson and GOP Senate candidate Tom Cotton 8-point leads over their Democratic opponents.)

Kansas is another place where a competitive Senate race—albeit a late-breaking one—could help turn the tides. Incumbent GOP Gov. Sam Brownback looked earlier this summer to be in serious trouble, and even now is running fairly close to even in polls against Democrat Paul Davis.

But the race between GOP Sen. Pat Roberts and independent candidate Greg Orman, which heated up in late August when the Democratic candidate dropped out, brought an influx of GOP money to the airwaves, and a ground operation for the GOP that was previously almost nonexistent.

Like Colorado, the issues at stake in the gubernatorial race are far different than those in the Senate race—Brownback's weakness comes from his own handling of the state's finances, as well as his efforts to elect more conservative members of the Legislature to enact those reforms in the first place.

Still, Wint Winter, who has organized the moderate Republican revolt against Brownback, said Roberts's and Brownback's troubles feed off each other—but that there's no doubt Brownback will fare better if Roberts does, and that the Roberts campaign's ability to turn out GOP voters will play a big role in Brownback's fate as well.

"A stronger Pat Roberts, a Pat Roberts that turns out more of the conservative vote, is more helpful to Brownback than it is to Davis," he said. "A weakened Roberts, a Roberts election campaign that doesn't turn out the base, is better for Davis."

Georgia, too, could see some spillover from the Senate race to the governor's race: National Democrats recently invested an additional $1 million into the Senate race to boost Democrat Michelle Nunn, which could end up helping Democratic gubernatorial hopeful Jason Carter as well.

To be sure, there are races where a competitive Senate race has had little or no effect on the gubernatorial race. Take Michigan, for example. At first both GOP Gov. Rick Snyder and GOP Senate candidate Terri Lynn Land looked to be competitive. But Land fizzled out, falling behind by double digits in the polls and prompting national Republicans to pull ad money out of the state—and Snyder, while in a close race, still holds the lead. There's also Iowa and New Hampshire, where GOP Gov. Terry Branstad and Democratic Gov. Maggie Hassan, respectively, look poised to cruise to reelection.

But on the whole, Senate races are having a big effect on the top of the ticket this fall—and in ways that will be tough to fully understand until the results are in on Election Day.

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