Sen. Barack Obama won't be making a stop at Penn State Beaver today.

He was to meet Western Pennsylvania voters during an appearance today at the campus in Center Township, but that was cancelled because he had to be Washington for key Senate votes.

After the cancellation, his next scheduled campaign appearance was to be this weekend in Indiana, one of the handful of states that will vote after Pennsylvania.

Like Mr. Obama, presidential candidates John McCain and Hillary Clinton also interrupted their campaign schedules to return to the Senate for votes on taxes and spending likely to become key points of contention in the race for the White House.