As tensions rise with Iran, Sen. Angus King gave President Trump credit on Friday for halting air strikes against the Islamic republic, but expressed deep concern that a mistake or a miscalculation could hurt chances of a diplomatic solution.

King said Trump’s decision to halt air strikes – planned as a response to Iran’s downing of a U.S. surveillance drone – was the right one. But King said he fears that hawkish advisers such as Secretary of State Mike Pompeo and National Security Adviser John Bolton could box in the president if escalation continues.

“What worries me is that steps could be taken by the secretary of state and the national security advisory that would limit the president’s options,” King said in a telephone interview. No one was hurt when the unmanned drone was shot down, but that calculation could change if there are future American casualties.

“Iran has been a malign actor for 40 years, and the question is what’s different this year, as opposed to 1985, 1995, 2007? And what’s concerning is we’re putting on pressure, which may work, but what if it doesn’t? It’s a high-stakes gamble.”

King said there is a risk that a defensive move by the United States could be interpreted as an act of aggression by the Iranians and that de-escalating such a situation becomes more and more difficult without an open line of diplomatic communication.

King, an independent, and Republican Sen. Susan Collins, both sit on the intelligence committee. Collins was unavailable for a phone interview and her office referred a reporter to comments the senator made during a TV interview in Bangor on Friday afternoon.

“We cannot allow Iran to continue to launch this kind of attack,” Collins said in the interview. “At the same time, the president is right to proceed very cautiously. A miscalculation by either the American side or the Iranian side could lead to a war in the Middle East, and that is something I don’t think anyone wants to see happen.”

Reps. Chellie Pingree and Jared Golden, both Democrats, blamed the current tension in part on the president’s decision to withdraw from the 2015 nuclear deal with Iran and impose new sanctions on the country.

“This is a crisis of President Trump’s making,” Pingree said in an emailed statement. “We had a plan, the JCPOA, for containing Iran’s nuclear ambitions. He ditched it and replaced it with nothing but vitriolic rhetoric and macho threats. Escalation started with President Trump and it is on him to de-escalate.”

Golden called that deal “imperfect but workable.”

“It should be possible to work with other countries to prevent Iran from getting their hands on nuclear weapons while also working with the rest of the world to condemn and combat Iranian aggression and their funding of terrorism across the Middle East,” Golden said in an email. “Those two things are not exclusive.”

Pingree also pointed to an effort to repeal the 2001 congressional war authorization that allowed President George W. Bush to go to war with al-Qaeda. That authorization has allowed presidents of both parties to justify war in the Middle East. While House Democrats passed that repeal Wednesday in an attempt to limit the president’s power, the Republican-led Senate is unlikely to do the same.

“The Constitution grants war-making power to the Congress,” Pingree said. “If the Trump administration thinks military action against Iran is justified, it must come to Congress and make its case, and get approval.”

A spokesperson for Golden did not answer a question via email about the congressman’s position on that repeal.

“We cannot let a hostile power like Iran off the hook, but we should all agree there is no sense in entering another military conflict in the Middle East unless absolutely necessary and that we must think long and hard about the use of force,” Golden said. “The president seems to have heeded the advice of military leadership and exercised restraint in the last 24 hours, which was the right thing to do.”