President Donald Trump’s Lawyer Ken Starr reminded senators on Monday that the Founders were concerned by the possibility of partisan impeachment, which is why there should be a high threshold for the proceedings.

Starr, the former independent counsel during the Clinton impeachment, opened up the president’s defense on Monday afternoon in a speech detailing the threshold of impeachment.

He said that the Founding Fathers made a “deliberate and wise choice” to restrain the power of impeachment wielded by Congress to help prevent frivolous impeachment efforts.

“Impeachments should be evaluated in terms of offenses against established law — especially with respect to the presidency,” he said.

The Founders, Starr argued, developed a common law threshold for impeachment requiring criminal activity to increase the “predictability” of the proceedings.

“To do what?” he asked. “To reduce the profound danger that a presidential impeachment will be dominated by partisan considerations, precisely the evil that the framers warned about.”

Starr stressed that previous presidential articles of impeachment efforts actually charged the president with actual crimes, such as the ones brought against former President Bill Clinton and former President Richard Nixon.

The common law of requiring criminal activity for presidential impeachment was “consistent with the constitutional text” and “consistent with the nation’s history” Starr said.

He argued that the current articles of impeachment against Trump did not meet the threshold of “high crimes and misdemeanors” set by the Constitution.

“Were crimes alleged in the articles in the common law of presidential impeachment?” he asked. “In Clinton, yes. In Nixon, yes. In this case, no.”