Less than a week after state Senate Majority Leader Dominic Pileggi publicly mulled a challenge to Sen. Bob Casey (D-Pa.), the high-ranking Harrisburg official took himself out of the running.

Pileggi wrote on his Facebook page Monday that “after a great deal of careful consideration, I have decided not to enter the race for the United States Senate.”

Several Republican candidates are challenging Casey. But there is no clear frontrunner yet for the GOP nomination, and even Republicans privately acknowledge that Casey will be tough to beat.