Former Pennsylvania Rep. Pat Toomey stopped short this week of formally announcing his candidacy for the Senate but made it clear that he’s much more likely than not to challenge veteran incumbent Arlen Specter for the Republican nomination.

Toomey, the president of the conservative activist group The Club for Growth, told the northeastern Pennsylvania radio station WILK-FM that he is “very close to making a final decision” and was “leaning toward running,” which would set up a rematch of a 2004 primary that Specter won by less than 2 points.

Toomey spoke to radio host Sue Henry after Specter told the same radio station on Monday that he wanted to move the Republican Party in a more centrist direction and that Toomey’s support for “deregulation, letting Wall Street run its own affairs” made him “part of the problem.”