This article is from the archive of our partner National Journal

On the surface, the Democratic Party looks remarkably unified heading into the 2016 presidential election, with Hillary Clinton scaring off any internal competition and Democrats rallying behind recruits in key Senate races. But there are divisions percolating within the party—ruptures that could grow more significant if setbacks occur on the road to a Clinton coronation.

Congressional races often serve as a leading indicator of what the future holds at the top of the ticket. And already, there are several primaries that would pit the Democratic Party's pragmatic liberal wing against the true-blue progressives. Democrats may not end up with significantly more contested primaries than in the past, but the ideological stakes will be higher. The battles are shaping up to be over core issues splitting the party: entitlements, support for Israel, national security, and others. The intraparty divisions that President Obama has suppressed and Hillary Clinton has avoided will be litigated down the ballot, and the stakes won't be for control of the Senate, but for control of the party's future.

Take the Maryland Senate race. Both Reps. Donna Edwards and Chris Van Hollen hail from the party's progressive wing. But Edwards is already aggressively pointing to Van Hollen's past openness to a grand budget bargain to draw a contrast with her challenger. "Our approach to Social Security must be absolute and non-negotiable," she warned in a recent fundraising email. That's not the only dividing line between Edwards and Van Hollen: She's one of the more outspoken Democratic critics of Israel, frequently voting with a small minority against symbolic, pro-Israel resolutions and winning enthusiastic support from J Street, a Jewish group that frequently criticizes Israel's policies.

(RELATED: Mikulski, Progressives Furious About Reid's Meddling in Maryland)

The potential for an ideological food fight is also growing in Florida, where one of the most moderate members of the Democratic caucus could be facing a nasty primary against one of the most pugnacious progressives. Rep. Patrick Murphy is the party favorite and fits the profile of a Democrat who's well-positioned to win a statewide race: centrist, backed by the Chamber of Commerce and, at 31, an up-and-comer. But Rep. Alan Grayson, who is acting increasingly like a Senate candidate, is already taking not-too-subtle jabs at Murphy. Without mentioning the congressman by name, he said the winning strategy in Florida wasn't to nominate someone who's "somewhat embarrassed to be a Democrat." If he enters the race, expect him to sharpen his attacks against Murphy.

Meanwhile, in Pennsylvania, the potential for intraparty unrest is high. Rep. Joe Sestak is the front-runner, but Democratic officials have been looking at possible alternatives. Sestak held a reliably liberal voting record during his time in Congress—and successfully challenged Arlen Specter in the 2010 primary by running to his left—but his regular criticisms of party leadership and occasional tweaks of President Obama's foreign policy decisions have created an opening for a more partisan Democrat as an opponent. Sestak's more muscular posture on America's role abroad and support for bipartisan solutions to tackle the country's fiscal challenges could create an opportunity for another Democrat to run to his left.

The prospect of a few competitive Democratic primaries normally wouldn't be worth noting. They pale in comparison to the messy, consequential fights that have divided the GOP over the last several election cycles. But what makes these looming battles relevant now is that they're a sign of the creeping demand for ideological purity among Democrats, as well as of the declining role of leadership in being able to shape the races to their liking. These are the same factors that led to the recent Republican skirmishes.

(RELATED: After Hours of Voting, the Republican Senate Passed a Budget. Now the Real Work Begins.)

And there are fresh signs that the Democratic Party's leaders are less influential in staving off primaries. Senate Minority Leader Harry Reid endorsed Van Hollen, ostensibly to dissuade Edwards from mounting a primary campaign, but she ignored his advice, announcing her candidacy four days later. Sestak bragged that he didn't inform the Democratic Senatorial Campaign Committee when announcing his campaign, playing up his independence from party leadership. Grayson met with the DSCC this week, and sounded more like a candidate after the meeting, even though Democrats hope to clear the field for Murphy. "I told them I'm going to run a Barack Obama type campaign if I run for the Senate," he told the Tampa Bay Times.

Losing has a way of stoking division: Republicans didn't face any of their internal problems until 2010, the first election in years in which they found themselves out of power. The seeds of conservative discontent were planted during the end of the Bush administration, when gripes over spending, immigration, and the role of the federal government first fell on deaf ears from party leaders.

Watch these primaries closely for signs of the Democratic Party's future. If Van Hollen's time in leadership is a nonfactor to Maryland Democrats, if Grayson's progressive ideology is more important than electability to Florida Democrats, and if Sestak can win the nomination without enthusiasm from party leaders, it's a sign that the grassroots are ascendant. And if Clinton doesn't win the White House, expect the murmurs of Democratic discontent to become a groundswell.

This article is from the archive of our partner National Journal.

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