WASHINGTON — President Trump warned Iran on Wednesday against using its proxy forces to attack American troops, vowing to retaliate by going “up the food chain,” a hint that the American military was considering a more direct strike on Iranian forces.
But senior Democrats cautioned Mr. Trump against attacking Iran without consulting Congress, a step he chose to forgo before the January killing of a top Iranian commander that pushed the countries to the brink of war. In a letter on March 27, Democratic leaders wrote that Mr. Trump must discuss with lawmakers any potential military actions overseas and noted that recent attacks on American forces in Iraq highlighted threats that could require a military response.
Mr. Trump strongly hinted on Wednesday that he was considering striking Iran if its proxy forces again attacked American troops and said his administration had “very good information” that Iran-backed militias were planning more assaults.
Noting that the United States had retaliated after a strike in March by Kataib Hezbollah, an Iraqi militia with ties to Iran, Mr. Trump suggested that if proxy groups struck again, the United States was considering directly attacking Iranian forces.
“If it happens again, that would go up the food chain,” Mr. Trump said. “This response will be bigger if they do something.”
Earlier on Wednesday, the president warned Iran against a “sneak attack” on American forces and hinted at reprisal. “Upon information and belief, Iran or its proxies are planning a sneak attack on U.S. troops and/or assets in Iraq,” Mr. Trump wrote on Twitter. “If this happens, Iran will pay a very heavy price, indeed!”
Mr. Trump’s comments were the latest indication that the White House was considering escalating action against Iran or its proxy forces.
Tensions with Iran have deepened since the start of the year when Mr. Trump ordered the killing of the top Iranian military and intelligence commander, Maj. Gen. Qassim Suleimani, who was plotting operations around the Middle East. Though both sides pulled back before a wider war broke out, a deadly tit-for-tat has unfolded inside Iraq in the weeks since.
But the lawmakers noted that the Constitution and American law require the president to consult with Congress “before engaging in military action or actions likely to lead to war,” outside of narrow situations of self-defense.
“This administration has largely failed to fulfill this legal obligation,” the lawmakers continued, mentioning the January drone strike that killed General Suleimani.
The letter was signed by the Democratic members of the so-called Gang of Eight, who are regularly briefed by intelligence agencies on sensitive national security developments: Speaker Nancy Pelosi; Representative Adam B. Schiff of California, the chairman of the House Intelligence Committee; Senator Chuck Schumer of New York, the minority leader; and Senator Mark Warner of Virginia, the top Democrat on the Senate Intelligence Committee.
The letter cited media reports about the administration’s consideration of direct action against Iran in response to attacks on American forces in Iraq by Iranian-sponsored militias. It was sent on the same day that The New York Times reported that the Pentagon was planning for a potential escalation in operations against Iranian militias.
Secretary of State Mike Pompeo and other officials have privately pushed for more direct attacks on Iranian forces, as part of an effort to force Tehran to the bargaining table.
Mr. Trump had resisted Mr. Pompeo’s proposal for tougher action, noting in the deliberations with his national security team that with Iran reeling from the coronavirus, a direct attack would appear inappropriate.
But Mr. Pompeo and some other senior administration officials have become frustrated with the violence in Iraq and near-daily American intelligence reports that Iran’s proxy forces are plotting against the United States. Mr. Pompeo, along with Robert C. O’Brien, the national security adviser, and Richard Grenell, the acting director of national intelligence, have argued that bolder action against Iranian forces could break the current cycle of violence and give new life to efforts to restart negotiations with Tehran.
Administration officials have maintained for nearly a year that a harsh approach toward Iran, including a campaign of financial warfare, would hurt Iran’s economy to the point of forcing its government to negotiate over its nuclear program and its military operations throughout the Middle East. Instead, Iran has lashed out with attacks for months against American forces and allied countries.
Mr. Trump held out hope on Wednesday that his tougher stance on Iran would restart negotiations. He said that he believed Tehran was “dying to make a deal” and that if Iran gave up its ambitions for nuclear weapons, it could get negotiations settled quickly.
Defense Secretary Mark T. Esper said the Iranian government had refused an American offer of medical supplies and had done too little to help its people fight the pandemic, instead continuing to support its proxy forces.
“I feel deep concern for the Iranian people,” Mr. Esper said. “The important thing is that the Iranian government should focus on them and stop this malign behavior that they’ve been conducting now for over 40 years.”
Senior military officers have been more skeptical of a stepped-up campaign against Iran or Iranian-backed militias in Iraq. In a memo, Lt. Gen. Robert P. White, the top American commander in Iraq, wrote that a new military campaign against the militias would require that thousands more American troops be sent to Iraq and divert resources from the training mission.
At his news conference, Mr. Trump said he was watching the situation in Iraq closely and had been in touch with the Iraqi government about the threats against American forces. He said his public comments were a message to Tehran to reconsider its attacks.
“It’s not a heads-up” about an attack, Mr. Trump said. “I’m giving them a warning. There’s a big difference. I’m saying if you do anything to hurt our troops, they’re going to pay a price.”