House Judiciary Chairman Jerry Nadler (D-N.Y.) said on Fox News Sunday that Donald Trump has "violated the law 6 ways from Sunday" and that he would be indicted if he were not president.

WALLACE: "Why are you putting Mueller and the country through this?"

NADLER: "We want the American people to hear directly from special counsel Mueller what his investigation found. The president and the attorney general and others have spent the last few months systematically lying to the American people about what the investigation found. They've said that it found no collusion, that it found no obstruction, that it exonerated the president. All three of those statements are absolute lies.

It found a great deal of collusion, it found a great deal of obstruction of justice by the president, and it pointedly refused to exonerate the president. We think it's very important for the American people to hear directly what the facts are because this is a president who has violated the law 6 ways from Sunday. If anyone else had been accused of what the report finds the president had done, they would have been indicted."

Why it matters: Nadler, whose committee is ultimately responsible for approving articles of impeachment, said the Mueller report presents "very substantial evidence" that Trump committed "high crimes and misdemeanors" — the marker for impeaching a president. And yet he has continued to stand behind House Speaker Nancy Pelosi's decision not to launch impeachment proceedings, even as support grows within the Democratic caucus.

Many believe that Mueller's public appearance before Congress on Wednesday will spurn a new wave of calls for impeachment, despite the fact that Mueller has said his testimony will not go beyond what's written in his 400-page report.

The notion of "educating the public" on Trump's alleged malfeasance has been core to the impeachment strategy of Democratic leaders, who have said they're waiting to get the public on board before moving forward.

Go deeper: Which House Democrats have called for impeachment