If Hillary Clinton wins her party's nomination, she'll be the most hawkish Democratic nominee since the Iraq War began.

Democrats have grown deeply skeptical of foreign wars since Iraq — a fact reflected in Barack Obama's more restrained foreign policy.

If Clinton skates to victory, she will take a more aggressive approach to world politics, pulling the party in a new direction without much of a debate. And if she were to win the presidency, both the party and American foreign policy itself could change in a big way.

Clinton has been out of step with Democrats on foreign policy for a long time

Clinton was Obama's Secretary of State, so she can't openly denounce his foreign policy while running for the Democratic nomination. But she has taken oblique shots that make her feelings clear: She believes the Obama administration's approach to world politics is too cautious.

"Great nations need organizing principles, and 'Don’t do stupid stuff' is not an organizing principle," she said in a 2014 interview with the Atlantic's Jeffrey Goldberg.

Many Democrats feel differently. In a poll released within weeks of that interview, a plurality of Democrats said America "does too much in helping solve world problems." But being out of step with the Democratic party is nothing new for Clinton: throughout the Obama administration, she has been consistently at odds with the majority of the party on key issues of war and peace.

And while, unlike the Republican candidates, Clinton has been fairly supportive of some of the Obama administration's foreign policy — she's cautiously supported the framework nuclear deal with Iran and broadly endorsed Obama's approach to fighting ISIS — she has also disagreed.

In mid-2009, then–Secretary of State Clinton was one of the key forces in the Obama administration advocating for a "surge" of new troops to Afghanistan. At the time, Gallup found that 62 percent of Democrats opposed sending more troops to the country.

In March 2011, she argued strongly for intervening to stop Muammar Qaddafi's slaughter of rebels in Libya. At the time, 57 percent of Democrats told Pew the US had no responsibility to stop the killing in Libya.

In 2012, Clinton and General David Petraeus presented Obama with a plan for arming the Syrian rebels fighting Bashar al-Assad's regime. Only a tiny minority of Americans — 11 percent — supported the idea, according to a June 2013 NBC/Wall Street Journal. The poll didn't disclose an exact partisan breakdown, but Democrats and Republicans broadly agreed: "whether you voted for Romney or Obama, they have the same opinion on Syria," Bill McInturff, one of the pollsters who conducted the poll, said.

Clinton doesn't regret these decisions today. In fact, she seems to think they've been vindicated. In her interview with Goldberg, she blamed the rise of ISIS partly on Obama's failure to arm the Syrian rebels in time. She defended the intervention in Libya. She compared the struggle against groups like ISIS and al-Qaeda to the Cold War.

So while she may not be openly criticizing Obama too much now, it's very clear that a President Clinton would bring far more hawkish instincts to bear on global problems than the current president — or, for that matter, your average Democratic voter.

The gap between Clinton and Democrats on foreign policy could fuel a primary challenge, but probably won't

When you've got a major ideological divide between a party's presumptive nominee and its base, you start to wonder whether there's going to be a serious primary fight. That's, of course, what happened in 2008. In part, Obama beat Clinton because she supported the Iraq War and he didn't.

And there are Democrats who have the background and the credibility to go after Clinton's position on global affairs. Former Sen. Jim Webb, who's exploring a presidential campaign, has a well-earned reputation as a relative dove.

"We have a tendency now, more than just about any time in my adult life that I can remember, to jump toward the military option very quickly," Webb told Ezra Klein. "In many, many cases, that isn't the best solution."

The senator, then, could very well be the kind of protest candidate that forces Clinton to deal with the fact that she's out of step with the party on foreign affairs. But his chances of winning on foreign policy alone are virtually nil.

First, Clinton is way more popular among Democrats than she used to be. In April 2007, about 35 percent of Democrats supported Clinton for president nationally, according to a RealClearPolitics average of polls. In April 2015, that number is 60 percent. (Webb gets 1.2 percent support, if you're curious.)

Second, she has way more support now among Democratic activists and elites — who play a crucial role in determining the ultimate nominee. One way to measure elite support is endorsements: as Andrew Prokop points out, Clinton is doing much better on that score in 2015 than she was in 2007.

Finally, the current Democratic divide is not like the split over the Iraq War. By and large, Americans don't vote on foreign policy. The only real exception is when there's a major crisis — like a war that's gone horribly wrong. Even though most Democrats are more dovish than Clinton, they almost certainly won't abandon her for someone like Webb for that reason alone.

This means the Democratic Party will be transforming on foreign policy without any real debate

If Clinton wins the nomination, the Democratic Party's official position on foreign policy will shift with her. And, in a subtler way, the rank-and-file's opinion will change, too. On foreign policy, Clinton will remake the Democratic Party in her image.

One of the basic facts of American politics is that partisan identity swamps ideology. When party leaders, particularly a president, take one opinion, it's more likely that the party with shift with her than outright oppose her.

That seems to be especially true on foreign policy, an issue that just isn't as important to Americans as social or especially economic issues. If Clinton stakes out more hawkish positions during the campaign, Democratic voters are likely to follow her.

We have actual evidence of this happening during the Obama administration. On the three big issues where Clinton tacked interventionist — the Afghanistan surge, the Libya war, and the arming of Syrian rebels — Democrat public opinion swung around after Obama publicly embraced Clinton's position (or at least, something like it).

After Obama announced that he'd be sending 30,000 new troops to Afghanistan in 2009, Democratic public opinion did a total 180. 58 percent of Democrats approved of the plan; again, 60 percent had previously opposed sending any new troops to the country.

Though most Democrats were skeptical that the US had an obligation to be in Libya before the war, that changed quickly: after Obama announced the US would be bombing, 59 percent of Democrats said the president had made the "right decision."

Arming the Syrian rebels is perhaps the most striking example. The poll that showed minuscule national support for arming the rebels was released on June 11, 2013. On June 13, Obama announced a plan to aid the Syrian rebels after evidence of chemical weapons use by the Syrian regime emerged. Then on June 17, a Gallup poll found that 51 percent of Democrats approved of "the Obama administration's decision to provide direct aid to Syrian rebels." A June 17 Pew poll that didn't mention the Obama administration found that 66 percent of Democrats opposed sending arms, suggesting that the mere mention of Obama's name was enough to change Democratic minds.

So when the Obama administration took Clinton's advice, and pursued a more hawkish course of action, rank-and-file Democrats supported it. There's very reason to think things would be different with Candidate or President Clinton: they'll back her play.

American foreign policy will change, almost no matter who wins

Facing little opposition from inside her party, Clinton will have a free hand to pursue a more aggressive foreign policy. It's impossible to predict exactly what that will look like in terms of specific policies. Foreign policy is so crisis-driven that it's hard to say what she'd do differently than Obama with any certainty. Plus the demands of the campaign mean that her criticism of Obama's record is, for the time being, fairly muted.

But we can hazard a few guesses. Clinton's rhetoric about Iran has been harsher than Obama's: if the Iran framework deal falls apart, she's more likely to seriously consider airstrikes than Obama is. She'll also likely to take a harder line on Iranian misbehavior around the Middle East, including its support for the Assad regime in Syria and meddling in internal Iraqi politics.

Similarly, Clinton could escalate US efforts against both ISIS and the Assad regime. She's consistently opposed the use of US combat troops against ISIS; assuming she sticks to that, she could significantly step up arms shipments to anti-Assad rebels (who also fight ISIS).

US troops are scheduled to withdraw from Afghanistan by the end of 2016. Clinton has signaled that she'd be open to negotiating a deal to keep a presence there longer.

Clinton is far from the only hawk in the race. With the exception of Rand Paul, virtually every Republican in the field is to Clinton's interventionist right on foreign policy. Barring a Paul surge (possible) or a Clinton collapse (unlikely), the race will be a competition between two relative hawks.

The battle for the Democratic party's soul — and, to a lesser extent, the future of American foreign policy — is looking like a fait accompli.

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