Story highlights "To sit here and wait doing absolutely nothing is the wrong thing to do," Steyer said.

The billionaire environmentalist said Trump has violated the constitution

Washington (CNN) Democratic mega-donor and billionaire environmentalist Tom Steyer on Sunday defended his $20 million national television and digital ad campaign calling for Congress to impeach President Donald Trump, saying "it's very important and urgent that we get him out of office."

"The fact of the matter is this President has performed in a lawless way throughout the campaign and throughout his presidency and he is an urgent threat to the American people," Steyer told CNN anchor Dana Bash on Sunday morning's "State of the Union." "So to sit here and wait doing absolutely nothing is the wrong thing to do. The American people want this man impeached."

Some Democratic leaders, including House Minority Leader Nancy Pelosi of California and Minority Whip Steny Hoyer of Maryland, have said now is not the time for House Democrats to push for impeachment.

"That should not be overturned except for the most egregious and demonstrable facts, and both Leader Pelosi and I believe it is not timely to address that issue given what is in front of us," Hoyer said earlier this month.

Other House Democrats, however, have called for Trump's impeachment, with Rep. Steve Cohen, D-Tennessee, introducing articles of impeachment earlier this month.