Former Rep. Pat Toomey (R)--president of the Club for Growth and the most high-profile potential threat to Sen. Arlen Specter (R-PA)--says he might enter the 2010 Senate race in his home state as a primary opponent to Specter, shaking up the race significantly.

In a statement issued today by the Club for Growth's press office, Toomey alluded to the Democratic stimulus package that has brought criticism on Specter, who was one of three Republicans in Congress to support it. Up until this point, Toomey had said he was seriously interested in running for governor.

Toomey said today:

As this disastrous recession worsens, I have become increasingly concerned about the future of our state and national economy.  Unfortunately, the recent extraordinary response of the federal government--more corporate bailouts, unprecedented spending and debt, higher taxes--is likely to make things worse.  I think we are on a dangerously wrong path.  Pennsylvanians want a US Senator focused on real and sustainable job creation that gets our economy growing again.  That is why I am considering becoming a candidate for the US Senate.

Specter's stimulus vote--at least immediately after he cast it--eroded some of his support in Pennsylvania, according to a Rasmussen poll published Feb. 13; Specter was also reportedly jeered by protesters in Pennsylvania shortly after the vote. Two weeks later, it's hard to say with authority whether that wave of discontent has kept up.

Beyond the campaign implications of Toomey's statement, the Club for Growth president could have made things more difficult for Specter--and for Democrats--in the Senate. Specter, as a moderate Republican who sometimes votes with Democrats, may find it harder to do so with a challenger from the right drumming up opposition among Pennsylvania's more ardent conservatives in a primary.

If that happens, Specter may not factor among Democrats' vote tallies as frequently as some on the left had hoped. With Democrats so close to 60 votes on their own, the votes of moderate Republicans like Specter can be deal breakers. And if the White House and the Democratic majority push ambitious legislation, Toomey's candidacy could make Specter harder to convince, depending on the political winds in Pennsylvania and how the veteran Specter reacts to them.

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