A day after House Democrats voted to formally authorize an impeachment inquiry into President Donald Trump, Speaker Nancy Pelosi on Friday told Pennsylvania Democrats that lawmakers had “no choice” but to pursue the investigation.

“No decision has been made to impeach the president,” Pelosi (D., Calif.) told hundreds gathered at the Convention Center for a state party fund-raiser. “That’s a question of what the inquiry will produce.

“Perhaps he will have some proof of innocence,” Pelosi said. “But no one is above the law, not even the president of the United States.”

Congress, she said, had an obligation to “protect and defend the Constitution of the United States.”

Mayor Jim Kenney, Gov. Tom Wolf, and U.S. Sen. Bob Casey were also on hand for what Democrats called their inaugural “Independence Dinner.”

Pelosi had already announced an impeachment inquiry into Trump in September. But Thursday marked the first time lawmakers cast a vote on the issue, a necessary procedural step that established the rules of the investigation.

Just two Democrats, including South Jersey’s Jeff Van Drew, voted against the resolution. No Republicans voted in favor of it.

The inquiry focuses on Trump’s pressuring of Ukraine’s president to conduct investigations that might harm his domestic political opponents. Democrats are investigating whether Trump held up nearly $400 million in military aid allocated by Congress as leverage against Ukraine’s leader.

A House committee has been hearing private testimony for weeks. Democrats say they expect to hold public hearings in the coming weeks as they prepare to draft potential articles of impeachment.

To impeach the president, Democrats would need a simple majority vote. The Republican-controlled Senate would then hold a trial. Removing the president would require a two-thirds vote.

» READ MORE: What impeachment is and how the process works

Trump has denied wrongdoing and called the inquiry a “witch hunt.”

“You can’t Impeach someone who hasn’t done anything wrong!” he wrote on Twitter Friday.

Kenney thanked Pelosi for her “commitment to protecting our Constitution and our democracy.”

“Tonight,” he said, “we begin the defeat of Donald Trump and his removal from the White House.”

On Saturday, Pelosi is scheduled to headline a fund-raiser in Philadelphia for Pennsylvania House Democrats who represent districts the GOP is expected to target in 2020. The beneficiaries include Rep. Susan Wild, who represents part of the Lehigh Valley, and Rep. Conor Lamb of Western Pennsylvania.