Democratic insiders are warning the party’s top 2020 contenders to avoid blaming the United States and sympathizing with Iran as they stake out opposition to President Trump’s evolving Middle East policy.

Political strategists and foreign policy thinkers on the Left are sharply critical of Trump for ordering a military strike to kill senior Iranian Gen. Qassem Soleimani, fretting it could draw the U.S. into another major war in the Middle East that the president is ill-equipped to manage. But some Democratic insiders are nevertheless uncomfortable with objections that are emanating from a few of their White House front-runners regarding Trump and his strategy to contain Iran.

“They want to avoid any sense that they’re being Iran’s lawyer. That’s the main thing, and some are better than others at doing that,” said Brian Katulis, a national security analyst with the Center for American Progress, a liberal think tank. “Then, they need to [explain] what they would do differently, and it can’t just simply be rejoin" the Iran deal.

“It can’t just be: 'Come home America,’” he added. “’Come home America’ wasn’t a great theme for [George] McGovern in 1972, and it’s not likely to work any better in 2020.”

The leading candidates — Joe Biden, Bernie Sanders, Elizabeth Warren, and Pete Buttigieg — immediately and aggressively denounced Trump for his decision to target Soleimani, who led the Islamic Revolutionary Guard Corps. This elite Iranian military force is responsible for the death of hundreds of American soldiers in the Middle East and for fomenting international terrorism.

Republicans are accusing Democrats of “Trump Derangement Syndrome.” In refusing to rally around the commander in chief and applaud him for eliminating an enemy of the U.S. with American blood on his hands, they are breaking with political precedent. Democrats are doing so just because they hate the president, and it will cost them in the November election, Republicans argue.

Democratic insiders with an eye toward winning the White House disagree.

Trump has politicized national security and made Iran into a “wedge issue,” they say. Charging Trump with aimless recklessness toward a bellicose Iran and offering a strategically sound alternative could pay huge dividends in the general election. But to avoid squandering this opportunity, party strategists say, Democratic contenders have to frame the argument properly and prevent Trump from painting them as unwilling to act to keep Americans safe.

“Everyone can agree it’s better off that [Soleimani] is not around," Democratic strategist Joe Trippi said. "Is it something that gets us into another long war in the Middle East? I don’t think there are a whole lot of Americans anxious for that.”

Warren perhaps has absorbed the most criticism.

After initially calling Soleimani a “murderer” but questioning Trump’s decision to take him out on strategic grounds — the critique many Democrats would like to see from their candidates — the Massachusetts senator shifted her criticism. She began describing Soleimani as a “senior foreign military official” who was assassinated. Sanders has used similar rhetoric, with Biden and Buttigieg sounding like Warren did originally, casting Soleimani as a bad guy who deserved his fate, but saying the move could backfire.

Still, some Democrats offered kudos to Warren and Sanders, saying that preventing another needless war transcends politics.

“I want to see these contenders do everything possible to stop us from getting into a war of choice with Iran,” said Democrat Dan Helmer, a Virginia state legislator and military veteran of Afghanistan and Iraq.