WASHINGTON – House Speaker Nancy Pelosi accused President Donald Trump on Thursday of perpetrating an "assault" on the nation's democracy after he told ABC News that he'd welcome foreign information on his 2020 opponent.

"It’s a very sad thing," Pelosi, D-Calif., said. "That's an assault on our democracy.

"What the president said last night shows clearly once again … that he does not know the difference between right and wrong," Pelosi said. "And that’s probably the nicest thing I can say about him."

The president told ABC's George Stephanopoulos he'd accept dirt on his 2020 opponent from a foreign government and might or might not turn it over to the FBI. Trump argued that such information amounts to "opposition research" widely used by campaigns.

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The House speaker said the law prohibits a campaign from accepting an in-kind contribution from a foreign government, which she said includes information.

Pelosi said she would pursue a "methodical" approach on deciding whether to launch an impeachment inquiry.

"Everybody in the county should be totally appalled by what the president said last night," Pelosi said. "But he has a habit of making appalling statements."

Earlier, Pelosi said Trump gave Russians a "green light" to meddle in the 2020 election.

"The Russians attacked our elections, and @realDonaldTrump is giving them the green light to do it again," Pelosi said in a tweet.

"They have information. I think I'd take it," Trump told ABC. "If I thought there was something wrong, I'd go maybe to the FBI – if I thought there was something wrong."

Trump said such political help would not be considered interference.

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Rep. Adam Schiff, chairman of the House Intelligence Committee, said Trump’s comments are a “dereliction of his duty,” but the California Democrat was not surprised by the admission.

"The Trump campaign sought such help in 2016, and their candidate just put out word they want more in 2020. It’s up to Congress to put a stop to it,” he said.

It wasn't only Democrats who raised concerns about Trump's position. Sen. Lindsey Graham, R-S.C., a close White House ally, said, "I think it’s a mistake of law.”

Contributing: Kristine Phillips and Michael Collins