On Friday morning, France’s deputy minister for foreign affairs echoed global concerns about President Trump’s unilateral decision to order the assassination of a top Iranian military commander, Maj. Gen. Qassim Suleimani, and other key Iranian and Iraqi figures.

“We are waking up in a more dangerous world,” Amelie de Montchalin said. “Military escalation is always dangerous. When such actions, such operations, take place, we see that escalation is underway.”

Secretary of State Mike Pompeo immediately announced that the French official was “wrong.” But by Friday afternoon, she had been proven right, when it was announced that the United States plans to send approximately 3,500 more troops—some arriving as early as this weekend—to the Middle East.

Where the escalation will end is an open question. House Speaker Nancy Pelosi pointed out that Trump is ordering military action “without an Authorization for Use of Military Force (AUMF) against Iran” and “without the consultation of the Congress.”

Even a few Republicans have raised constitutional concerns. Kentucky Senator Rand Paul argued that any move toward a broader war requires congressional authorization. “A war without a Congressional declaration,” warned Paul, “is a recipe for feckless intermittent eruptions of violence with no clear mission for our soldiers. Our young men and women in the armed services deserve better.”

Congressional Progressive Caucus cochair Mark Pocan, a Wisconsin Democrat who has been one of the chamber’s loudest advocates for diplomatic rather than military responses to challenges in the Middle East, is particularly worried that mistakes of the past will be repeated—in the Middle East, and in Washington.

“Trump’s unilateral decision to escalate tensions in the region by assassinating Iranian General Qasem Soleimani without any notification to or approval from Congress is wrong, it will destabilize the region and further endanger the lives of innocent Americans, Iranians, and Iraqis,” says the representative. “The President has repeatedly shirked diplomatic priorities in pursuit of military action across the Middle East, and he is on the brink of starting a wholly avoidable and unnecessary war with Iran.”

Pocan sought to avoid precisely this imbroglio when he emerged last year as a leading critic of the 2020 National Defense Authorization Act. That put him at odds not just with the Trump administration but also with House Democratic leaders, who repeatedly failed to effectively check and balance presidential war making during President Barack Obama’s tenure and have been only slightly more aggressive since Trump took office.

In 2019, anti-war House Democrats and a small group of libertarian-leaning Republicans (such as Kentucky Representative Thomas Massie) sought to use the NDAA as a vehicle to rein in the administration. In July, Pocan joined Oregon’s Earl Blumenauer, New York’s Adriano Espaillat and Alexandria Ocasio-Cortez, California’s Barbara Lee, Minnesota’s Ilhan Omar, Massachusetts’s Ayanna Pressley, and Michigan’s Rashida Tlaib in voting against the House’s $733 billion version of the defense budget. Last month, when the final version of the NDAA, with a $738 billion price tag and even fewer limits on the president, came back to the House, Pocan and 40 Democrats, six Republicans, and one former Republican turned independent (Michigan Representative Justin Amash) voted “no.”

“One of the biggest problems with the NDAA was the spending increases, which fund these endless wars. But we also wanted to make sure that the United States didn’t get involved in new conflicts in the Middle East without congressional authorization,” Pocan told The Nation Friday morning. “We had particular concerns that wrong actions could happen without consultation. What we’ve just seen reaffirmed the fears that we had.”

California Democrat Ro Khanna spoke to those concerns Thursday evening. “There were two amendments stripped from the NDAA that could have prevented tonight’s escalation,” he noted. “My amendment to prevent funding for war with Iran without Congressional approval [and] Barbara Lee’s amendment to repeal the 2001 AUMF.” An exasperated Khanna tweeted Thursday night: “Any member who voted for the NDAA—a blank check—can’t now express dismay that Trump may have launched another war in the Middle East.”

Lee expressed her frustrations Friday morning, explaining,

Since day one, Trump and his war hawk administration have shunned diplomacy by ending the effective Iran nuclear deal, and have had no real strategy or plan to replace it. The Trump Administration has acted without any consultation with Congress or an authorization to use military force. It is beyond clear that Congress must act urgently to repeal the 2001 and 2002 Authorization of the Use of Military Force (AUMF). My amendment to repeal the 2002 AUMF was included in the House-passed FY2020 NDAA, but stripped by Republicans from the final bill. We must work to prevent further military action in the region. We have known for years that there is no military solution, and it’s past time to return to a diplomatic strategy with our allies. We must protect our national security, our brave troops, our allies, and the American people.

Pocan share’s Lee’s sense of urgency. “We have to make sure that this doesn’t turn into another endless war,” he argues. “You have to expect that this [air strike] is going to escalate tensions. Congress needs to hear why the president thinks this was a necessary step and what we are going to do next in regard to whether this escalates to another war-like situation. We have to be concerned about the prospect that the president hasn’t thought through his actions.”

The frustration with Trump is warranted. But so, too, is a measure of frustration with congressional leaders from both parties, who have long failed to make a priority of the checking and balancing of presidents when it comes to matters of war and peace. On these issues, the prospects for building anti-war coalitions that include at least some Republicans are real—as was confirmed by last year’s bipartisan House and Senate votes for measures to end US support for the Saudi-led coalition’s unlawful attacks on Yemen. This week’s events are a stark reminder that Democratic leaders in the House and Senate should have worked much harder in 2019 to make the NDAA a tool for checking and balancing Trump on Iran.

Now, Democrats and at least some Republicans worry that Trump’s actions will lead to instability and perhaps war. It’s time that Democratic leaders stop sending mixed signals and act to avert another catastrophe in the Middle East. Some good steps have been taken; for instance, Senator Tim Kaine has introduced a war powers resolution to force a debate and vote in Congress to prevent further escalation of hostilities with Iran. And Vermont Senator Bernie Sanders and Representative Ro Khanna are introducing legislation that would block funding for any military action “in or against Iran” that does not have congressional authorization.

But that’s not enough. There must be a greater sense of mission with regard to the reassertion of congressional authority over military decisions regarding Iran, Iraq, and the whole of the Middle East.

“Our nation must avoid another endless war in 2020 and the potential senseless loss of millions of lives,” Pocan says, as he argues for a policy that would “de-escalate military action and instead prioritize diplomacy to secure peace in the region.”