It takes 67 senators to convict the former president, which will require 17 Republicans to join 50 Democrats.By Jon Delano

WASHINGTON, D.C. (KDKA) — The second impeachment trial of former President Donald Trump begins on Tuesday in the U.S. Senate.

It will take two-thirds, or 67 senators, of the 100 to convict Trump. That’s a high hurdle in any impeachment case, especially in one where the president is no longer in office.

READ MORE: Law Enforcement Identifies Victims Of Double Homicide At Westmoreland County Home

Four presidents have faced impeachment charges, although Richard Nixon resigned before Congress took action.

Only Trump has faced two impeachment trials, this time for inciting his supporters to violence with false claims about the election.

“I am going to listen to the arguments on both sides and make the decision that I think is right,” says U.S. Sen. Pat Toomey, a Pennsylvania Republican.

Both Toomey and U.S. Sen. Bob Casey, a Democrat, are jurors at this trial and say they have open minds. The trial will begin with some legal arguments.

“We’re going to be hearing a couple of hours’ worth of constitutional arguments before we even get to the presentation of the cases,” Casey told KDKA political editor Jon Delano on Monday.

Trump’s lawyers will argue that a president, once out of office, cannot be convicted of high crimes and misdemeanors. Both of Pennsylvania’s senators push back on that idea.

“I disagreed with their assessment. I think it is constitutional,” Toomey told CNN on Sunday. “I think it is clearly constitutional to conduct a Senate trial with respect to an impeachment. In this case, the impeachment occurred prior to the president leaving office.”

READ MORE: Pittsburgh Police Locate Missing 32-Year-Old Keith Walker

Casey says it makes no sense to allow any president to violate his oath of office during the last weeks of his presidency and not hold him accountable.

“I think common sense would tell you that you don’t want that kind of dynamic in a presidency,” says Casey.

Once that debate is over, House impeachment managers — the prosecutors — will show video clips from Trump’s speeches and the subsequent violence at the Capitol that led to five deaths, attempting to draw a link between the two.

“I think there’s a lot of evidence on the record already, and I think we will hear some more. But that will be a question that we’re called upon to determine,” says Casey.

To convict the former president, it will take 67 senators, which will require 17 Republicans to join 50 Democrats.

Will enough Republicans vote to convict Trump?

“I think it’s very unlikely,” said Toomey.

MORE NEWS: Crews Respond To 3-Alarm Fire In Pittsburgh's Bloomfield Neighborhood

Casey says the trial could last over the weekend until next Wednesday.