Specter, Toomey Senate primary comes down to Fight of the Right: "Since he mounted his campaign more than a year ago, Toomey, 42, has pinned his hopes on getting Pennsylvania's conservatives to turn out in droves for the April 27 primary. The three-term congressman's campaign marks the strongest primary threat to a sitting senator this year.

"The Pennsylvania race is being carefully watched as Republicans' slim 51-seat majority in the U.S. Senate hangs in the balance. It also is considered a litmus test of the strength of the GOP's right wing by national conservatives who are pouring more than $1 million worth of contributions and attack ads into the state to help Toomey.

"Specter, the 74-year-old Senate veteran who is seeking an unprecedented fifth term in Pennsylvania, is campaigning like he's running for his political life. His politically moderate Senate voting record—supporting abortion rights, scaling back the first round of President Bush's tax cuts in 2001 and scuttling the 1987 Supreme Court nomination of Robert Bork—has long angered conservatives."