WASHINGTON, D.C. — Evidence that President Donald Trump’s eldest son welcomed the Russian government’s help in his father’s campaign outraged Republicans in Congress on Tuesday, driving senators to demand more answers, and fast, as a new lane of inquiry opened in congressional probes of potential collusion with the Kremlin.

“Other shoes will drop before this thing is over,” said Sen. John McCain, R-Ariz.

“The emails are very problematic, very disturbing,” Sen. Lindsey Graham, R-S.C., said of the email chain that Donald Trump Jr. released Tuesday.

“If you’re ever approached about getting help from a foreign government, the answer is no,” said Graham, a senior member of the Senate Judiciary Committee.

Trump Jr.’s emails, released as the New York Times was prepared to publish, sparked calls even from some conservatives for the president to step down as Democrats began to utter the word “treason.”

At the Capitol, committees pressed for more information and possibly an appearance by Trump Jr. And the president’s legislative agenda, already in deep trouble, was now on even shakier ground.

Republicans control both chambers of Congress, and are feeling new, intense pressure for a signature victory. As Trump Jr.’s email dominated Capitol Hill hallway chatter, it became clear that the GOP will have to proceed without the help of a friendly, let alone influential, White House.

“That’s the very thing we need to not be distracted by,” said Sen. Thom Tillis, R-N.C., of the latest campaign controversy.

Senate Majority Leader Mitch McConnell, R-Ky., announced the extraordinary step of shortening the Senate’s five-plus-week summer recess to try to move an agenda that was bogged down even before Trump Jr. took to Twitter Tuesday.

McConnell deflected questions about the emails and whether he has confidence in the president’s dealings with Russia.

“The investigation in the Senate’s being handled by the intelligence committee, and I’m sure they’ll get to the bottom of whatever may have happened,” McConnell tersely told reporters.

Trump Jr.’s emails were the most specific evidence yet that Trump campaign officials and family members were eagerly taking help from the Russian government during the 2016 campaign against Democrat Hillary Clinton.

In the email exchange between Trump Jr. and publicist Rob Goldstone, the pair set up a meeting between Trump Jr. and Russian attorney Natalia Veselnitskaya. Goldstone told Trump Jr. that there are “official documents and information that would incriminate Hillary and her dealings with Russia and would be very useful to your father.”

“This is obviously very high level and sensitive information but is part of Russia and its governments support for Mr. Trump,” Goldstone wrote on June 3, 2016.

“If it’s what you say I love it especially later in the summer,” Trump Jr. replied in part, less than 90 minutes later.

The meeting took place several days later and was attended by Trump campaign manager Paul Manafort and Trump’s son-in-law Jared Kushner. Veselnitskaya has denied she works for the Russian government. Trump Jr. said she did not provide any information about the Clinton campaign.

Graham wanted to know more.

“I find it odd they would refer the Trump campaign to a lady who knew nothing about the Clinton campaign. But on its face it’s problematic,” he said.

Congressional committees and federal investigators are actively probing possible links between Trump campaign advisers and Russia during the campaign. U.S. intelligence officials have found that Russian President Vladimir Putin directed a campaign to aid Trump while hurting Clinton. Trump has contended the investigations are a “witch hunt.”

The next step in Congress is likely to be an appearance by Trump Jr. before either the Senate intelligence or judiciary committees.

The intelligence panel, chaired by Sen. Richard Burr, R-N.C., has taken the lead in the Russia investigation. He wouldn’t get specific about what’s coming next.

“We’re interested in talking to anybody that brings any degree of clarity to the investigation,” he said.

Burr said the Trump Jr. email chain “looks interesting.”

But, he added, “I don’t know, I’ve seen three different exchanges. There seems to be more to it. The important thing is the context that it happened in. Nobody knows that.”

Sen. Dianne Feinstein of California, top Democrat on the judiciary committee, wants Trump Jr. before that panel.

“There are still many questions that must be answered,” Feinstein said. “That’s why I’ve urged (Senate Judiciary Committee Chair Charles) Grassley to move quickly — this issue is squarely within the jurisdiction of the judiciary committee and I believe we need to have Donald Trump Jr., and other individuals come before the committee, in open session, as soon as possible.”

Grassley, R-Iowa, credited Trump Jr., for his transparency in putting out the emails. “I think that he’s showing that he wants everybody to know what the situation is,” the senator said.

—-

But other Republican lawmakers shared Feinstein’s concern and in some cases, her outrage.

McCain and Graham said they don’t know whether Trump Jr. violated any laws by meeting with the Russian attorney but agreed that he exercised questionable judgment, knowing that a representative of a foreign country was allegedly offering information that could influence the U.S. election.

“I don’t know if any law was broken here, but the willingness to receive help was a mistake,” Graham said.

McCain recalled that he was in a similar situation to Trump Jr.’s earlier this year he was in Halifax, Nova Scotia, and was approached by someone who said he had information concerning Trump’s activities while he was in Moscow.

“I said ‘fine.’ I sent a guy over. Guy got it. Guy brought to me, I looked at it, I said ‘This belongs with the FBI,’” McCain said. “That’s what you do. That’s what I did.”

Sen. Mark Warner of Virginia, top intelligence committee Democrat, said the emails are simply the latest example in a “pattern” of Trump campaign officials or associates admitting to meetings with Russians after first denying them.

“This excuse of naivete or rookie attitudes,” Warner said, “you know, lying is not a rookie mistake.”