Sen. Chris Murphy (D-Conn.) confirmed Tuesday that he met with Iran’s foreign minister in Germany over the weekend, drawing criticism from conservatives, including President Trump, who suggested the senator may have violated an obscure law that prohibits U.S. citizens from negotiating with foreign governments.

In a sprawling Medium post, Murphy explained that he sought out Mohammad Javad Zarif at the Munich Security Conferenceon Saturday to bolster diplomatic relations between Iran and the United States, which have worsened in recent years.

Murphy said the preeminent reason behind the meeting was simple: “It’s dangerous not to talk to your enemies.”

“I have no delusions about Iran — they are our adversary, responsible for the killing of thousands of Americans and unacceptable levels of support for terrorist organizations throughout the Middle East,” he wrote. “Discussions and negotiations are a way to ease tensions and reduce the chances for crisis. But Trump, of course, has no such interests.”

Murphy’s tête-à-tête was first reported Monday by the Federalist, a conservative publication, which accused the senator of “stonewalling” about his conversation with Zarif.

The report prompted confusion from the Trump administration, which claimed it didn’t know about the meeting, and it incited outrage among the president’s supporters and political allies, who accused Murphy of violating the Logan Act, which bars U.S. citizens from interfering in foreign diplomacy.

On Tuesday, Trump echoed the accusation, which was then circulating in right-wing media. “I saw that Sen. Murphy met with the Iranians, is that a fact?” Trump asked reporters Tuesday before boarding Air Force One at Joint Base Andrews. “I just saw that on the way over. Is there anything I should know? Because that sounds like, to me, a violation of the Logan Act.

“What happened with that?” Trump continued. “They ought to find out about if it’s true. I don’t know.”

The Logan Act stems from a 1799 statute, and no one has ever been convicted of violating the law. The last time someone was charged under it was 1853, yet the law has made headlines several times since Trump took office.

In 2017, some experts said former national security adviser Michael Flynn may have run afoul of the Logan Act when he discussed U.S. sanctions against Russia with that country’s ambassador in the month before Trump took office. Murphy was among Flynn’s most vocal critics at the time, pushing for an investigation into the retired Army general’s actions.

Last year, Trump accused former secretary of state John F. Kerry of meeting with Iran’s leaders and undermining his administration’s policy toward the country — especially concerning the Obama-era nuclear deal that Trump scrapped.

“John Kerry speaks to them a lot, and John Kerry tells them not to call,” Trump said then. “That’s a violation of the Logan Act, and frankly he should be prosecuted on that.”

Kerry’s spokesman later said the president was “simply wrong, end of story.”

Current Secretary of State Mike Pompeo, who has also criticized his predecessor’s contacts with Iran, said Tuesday that he wasn’t aware of Murphy’s meeting with Zarif.

“If they met, I don’t know what they said,” Pompeo told reporters during a trip to Ethiopia. “I hope they were reinforcing America’s foreign policy, not their own.”

Murphy isn’t the first senator to meet with Zarif in recent months. In July, Sen. Rand Paul (R-Ky.) sat down with the Iranian official after first coordinating with the White House and the State Department, the New Yorker reported. They discussed Iran’s nuclear program and tensions in the Persian Gulf, and Zarif told the publication, “I always see people from Congress.”

Emma Ashford, a research fellow at the Cato Institute, a libertarian think tank, applauded Murphy’s expedition and compared it with Paul’s.

“Good on Chris Murphy for meeting with Zarif and promoting dialogue,” Ashford said on Twitter. “I hope that @RandPaul — who met with Zarif last year for similar reasons — will point out to Trump why such diplomacy is a good thing.”

But Doug Stafford, a Paul adviser who was at the Zarif meeting, replied to Ashford that the circumstances of the two senators’ confabs were very different.

“Diplomacy is a good thing,” Stafford wrote. “But we met with Zarif at POTUS request. Meetings themselves are not necessarily an issue but of course we also don’t need 100 Senators doing their own foreign policy either.”

In his post, Murphy said there has been “no diplomatic channel” between the United States and Iran in the past three years and suggested tensions between the two countries reached a breaking point in January, when Iranian missiles struck two Iraqi bases housing U.S. military personnel. The attack — which Iran launched in retaliation for the United States’ killing of Maj. Gen. Qasem Soleimani the week before — left dozens of U.S. troops with traumatic brain injuries.

Murphy detailed how he approached Zarif about improving U.S.-Iran diplomacy, including asking the foreign minister about the possibility of additional Iranian retaliation over Soleimani’s killing. Murphy also said he inquired about Iran’s support for the Houthi rebels in Yemen and U.S. citizens being unlawfully detained in Iran.

The senator emphasized, however, that as a rank-and-file lawmaker, he “cannot conduct diplomacy on behalf of the whole of the U.S. government, and I don’t pretend to be in a position to do so.”

“But if Trump isn’t going to,” he added, “then someone should.”

Read More: