As the second impeachment trial of former President Donald Trump gets underway, a political expert says its outcome depends on how Republicans will vote.

Dr. Anthony Dell'Aera says there is an argument by Republicans that impeachment is unconstitutional because Trump is no longer president, and up to this point, all but five have supported this claim.

This argument will be debated during the Senate trial process, and Dell’Aera says it's likely we won’t see a lot of change in the senators’ positions.

"It's an important signal to look for as we follow the events of this week, because it's probably a harbinger of where the rest of the trial will go,” he said. “If you are beginning from a starting point in which 45 Republican senators believe the process is unconstitutional, then it casts serious doubt on whether there are enough votes to convict.”

To convict on an impeachment charge requires a two-thirds vote of the Senate. Seventeen Republicans would need to join all 50 Democrats, which Dell'Aera says is a large leap to make.