Even if Brown were to win an expected late spring special election for the Senate — he would enter as a favorite — he’d have to pick up and do it all over again next year, in a higher-turnout contest that could also be tough to win. A loss in that race could end his political career.

That all makes for a wrenching decision for Brown: To make another run at Capitol Hill or hold off for the chance to reign over Beacon Hill. Sources tell POLITICO he has not made up his mind.

“My sense is that Scott has a good chance of succeeding if he decides to enter the special,” said Republican National Committeewoman Kerry Healey, who served as Romney’s lieutenant governor. “However, there’s a lot of appeal to waiting for the governor’s seat. … There are opportunities in both.”

The tug of history is toward a gubernatorial run: Bay State Republicans simply fare much better running for state offices than federal offices. Republicans, including Romney, held the governorship from 1991 to 2007. When Brown won the late Ted Kennedy’s seat in a January 2010 special election against Attorney General Martha Coakley — who ran what many observers consider one of the most incompetent campaigns in modern political history — he became the first Massachusetts Republican elected to the Senate since 1972.