WASHINGTON ― By exchanging emails about potentially incriminating information about former Democratic presidential nominee Hillary Clinton last summer, Donald Trump Jr. may have violated federal election law, Democrats said Tuesday.

Moments after The New York Times broke the story detailing the emails on Tuesday, the president’s oldest son responded by tweeting screenshots of the emails. The emails discussed an effort on behalf of the Russian government to aid Donald Trump’s campaign for president.

“If it’s what you say I love it especially later in the summer,” Trump Jr. told music publicist Rob Goldstone, an acquaintance with ties to Russia, in one email.

Jared Kushner, the president’s son-in-law and now-White House adviser, as well as his then-campaign manager, Paul Manafort, later joined Trump Jr. in a meeting with a Kremlin-linked lawyer who claimed to possess the anti-Clinton information.

Democrats on Capitol Hill said it looked like Trump Jr. may have broken federal campaign finance law by soliciting assistance from a foreign government. Nearly all Democrats ― and some Republicans ― also called on Trump Jr. to testify publicly before the Senate about the nature of the meeting.

“You have the appearance,” Sen. Dianne Feinstein (D-Calif.), the ranking member on the Senate Judiciary Committee, said when asked by HuffPost if the president’s son had broken the law. “Now, I can’t say because I don’t know more than that, but certainly the appearance is there.”

Feinstein added that it was “premature” to discuss allegations of treason, a subject Sen. Tim Kaine (D-Va.), Clinton’s vice-presidential nominee, floated earlier Tuesday.

Sen. Brian Schatz (D-Hawaii) said that “it looks like laws were violated.”

Sen. Claire McCaskill (D-Mo.) said she believed there is “some pretty clear evidence of campaign finance violations at this point.”

On the other side of the Capitol, Rep. Grace Meng (D-N.Y.) sent a letter to the Federal Election Commission calling for an investigation into whether Trump campaign officials violated elections law by meeting with the Russia-linked lawyer.

“It is against the law for a person to accept any contribution from foreign national in connection with American election,” Meng said.

Some Democrats said the Trump campaign sought to openly collude with the Russian government.

“For a long time, we saw a lot of smoke, but no fire. You’re seeing fire today,” Sen. Chris Murphy (D-Conn.) told reporters. “I’m not an expert on the law of treason, but this starts to look like open, knowing collusion with the Russian government.”

Murphy added: “Either the president knew about this meeting and he was lying about it, or he was running an operation in which he allowed for his closest advisers to freelance collusion with the Russian government.”

Sen. Ron Wyden (D-Ore.), minced no words. He said in a statement that “there is no longer a question this campaign sought to collude with a hostile power to subvert America’s democracy.”

Sen. Mark Warner (D-Va.), the ranking member on the Senate Intelligence Committee, which is conducting its own investigation into Russia’s meddling in the election, said he was suspicious of the timing of Trump Jr.’s emails because they predated by weeks the hacking of the Democratic National Committee, whose email leaks Trump cited frequently on the campaign trail.

Warner dismissed the notion that Trump Jr.’s meeting with a Russian-linked lawyer could be shrugged off because he was a novice at politics.

“Lying is not a rookie mistake,” Warner said, referring to Trump Jr.’s initial statement that claimed the meeting with the Russian lawyer was primarily about adoptions.

Other lawmakers simply expressed their disbelief about the Trump Jr. emails.

“I just couldn’t believe it. It gets more bizarre every day,” a stunned Sen. Joe Manchin (D-W.Va.) said.

Sen. Martin Heinrich (D-N.M.) echoed the sentiment.

“We’re at a very unusual time in history, and I hope people start putting their country first,” Heinrich said.