Politics rules on Capitol Hill. It swings both ways, influencing both political parties.

Consider what might be about to happen.

President Barack Obama, a Democrat in the final full year of his second term and final term, is likely to name someone to fill a vacancy created by the death of Supreme Court Justice Antonin Scalia.

The U.S. Constitution grants him the authority to do so. It also grants the Senate the authority to approve anyone nominated to the court.

The Senate is controlled by Republicans.

Democrats and Republicans don’t like each other much these days. Republicans really dislike the Democrat in the White House and the feeling appears to be quite mutual.

What’s the president going to do about this high court vacancy?

One theory getting kicked around in the hours and days after Scalia’s death is that the president could name an appellate judge who’s already been approved by the Senate. One name has emerged as a possible favorite, Judge Sri Srinivasen, an Indian-American who was approved unanimously the Senate before he took his federal appeals court seat.

He’s apparently thought of as a moderate. He doesn’t lean far left. He surely doesn’t lean far right. He shoots straight down the middle, according to a number of legal experts.

So, will this fellow breeze through the confirmation process as he did when the Senate considered him for a lower court?

OK. You can stop laughing.

Republicans are vowing to deny the president any action on a pending nomination. They want to wait until after the November presidential election in which they hope a Republican wins the White House.

Democrats will have none of that. They want the president to make a nomination and they want the Senate to vote on it. Quickly.

Why not select someone who’s already been vetted by the Senate? Would a judge like Sri Srinivasen be just as qualified to sit on the Supreme Court as he is on a lower court?

Well, in my version of a perfect world, it would seem like a natural for the president to find a moderate judge who’s already been approved. Except that he would be succeeding a towering figure of the judicial conservative movement.

Scalia led what has been called a “conservative renaissance” on the Supreme Court. Anyone — regardless of credentials, standing among peers or legal brilliance — is going to be run through a political sausage grinder.

Politics. Sometimes it’s downright ugly.

And sometimes it doesn’t serve the nation well.