Former Pennsylvania congressman Joe Sestak is planning to run for Senate, not governor, he announced today, setting up a rematch in 2016 with the man who beat him two and a half years ago.

"Today, we're launching a campaign for leadership, for a better America," Sestak said in a video announcing his bid. "The Senate needs a leader accountable only to we the people, not any other interest."

The retired Navy admiral defeated then-Sen. Arlen Specter in a 2010 Democratic primary but lost that fall to Republican Pat Toomey.

There was some buzz that Sestak would run against Gov. Tom Corbett (R) in 2014; a recent Quinnipiac poll had him leading the governor by 14 points. Rep. Allyson Schwartz, a Democrat who launched her gubernatorial campaign in April, was ahead of Corbett by 13 points in the same survey.

Sestak has formed an exploratory committee, which is the equivalent of launching a campaign in terms of the FEC paperwork.