Critz could challenge Shuster in incumbent head-to-head

Rep. Mark Critz (D-Pa.), whose district is likely to disappear due to redistricting, is seriously considering a challenge to Rep. Bill Shuster (R-Pa.), according a source close to Critz.

Pennsylvania is losing a congressional district, Republicans are in control of the redistricting process and the western part of the state where Critz's district is located has seen the slowest population growth, making him an easy target for the GOP.

Republican lawmakers will likely axe his district and split it up among the surrounding Republican districts while giving some of the Democratic parts of the district — including Critz's home — to Rep. Jason Altmire (D-Pa.). Early expectations were for Critz to challenge Altmire in a primary for a slightly Democratic-leaning seat, but the source says Critz is much more likely to challenge Shuster.

It would be an uphill fight. Republicans are unlikely to add too many Democratic voters to Shuster's district, which gave Sen. John McCain (R-Ariz.) 63 percent of its vote in 2008.

But Critz has proven himself a tough candidate, winning a 2010 special election in a marginal district by eight points and holding onto his seat in the Republican wave election that fall. He is pro-gun rights and anti-abortion rights, and opposed Democrats' healthcare and cap-and-trade legislation in 2010.

Depending on the exact lines of the final district, Critz could give Shuster a real challenge.