One of the right's arguments as to why Pat Toomey can win his Pennsylvania Senate race is that he won election three times in a congressional district that leaned toward the Democrats from 1998-2004.  In fact, the district had an ever-so-slight Republican tilt compared to the nation as a whole when Toomey won it (which means that it leaned even more heavily toward Republicans when compared to Pennsylvania as a whole), but it is a fair overall point:  Toomey's district was, at the very least, a swing district when he was elected.

But there is an important caveat here.  The 2000 Politics in America (which covers the 1998 election) states: "He is viewed as a moderate on social issues such as abortion rights, which he supports."   After Toomey's first term, Politics in America again wrote "[o]n social policy issues, he is viewed as a moderate -- supporting, for example, abortion rights."

I did some more digging, and came up with the following from LifeNews, reporting on the 2004 Toomey-Specter primary:

The Specter campaign is circulating a memo which calls into question Toomey's pro-life credentials. The memo states that, in 1998, Toomey cast himself as the only Republican candidate in his Congressional race that supported legal abortion. At the time, Toomey said that abortion should be legal if completed in the first trimester of pregnancy.

The LifeNews article goes on to explain that "once he was shown the truth about abortion, [Toomey] became pro-life--and he's never looked back." Setting aside any question about Toomey's motives for changing his views, or any other social issue flip-flops (which in any event surely pale in comparison to Specter's party flip-flop), it is important to remember that, while Toomey did win a swing district in the late 90s, he presented a different ideological profile to the voters on social issues than he does today.  Of course, these are the exact issues that are expected to give Toomey the most trouble in the Philadelphia suburbs.  So we probably shouldn't assign too much weight to Toomey's victories in a swing district.