We ended up with Specter due to a combination of factors. Liberal Republican Senator Richard Schweiker retired. Specter won a multi-candidate Republican primary due to better name I.D., as he had run for Senator in 1976 and Governor in 1978. He lost both primaries, but they gave him name recognition in central and western Pennsylvania. Also, his many years as Philadelphia County District Attorney made him a celebrity in the metropolitan Philadelphia area. The rejection of Jimmy Carter handed him the general election.
In the ‘80 GOP primary, it was an 8-man field, but 5 of them were effective unknowns, leaving the three leaders, State Sen. Edward Howard, “Bud” Haabestad and Specter. Specter was the liberal in the race and Haabestad was the Conservative. The 5 lesser candidates received between 5 and 3% apiece. Howard received 13%, but Specter eked by with an underwhelming 36% and Haabestad got 33%. Had almost any of the lesser candidates endorsed Haabestad, he’d have won the nomination. As it was, Specter won again by a very underwhelming 50%-48% against Pittsburgh Mayor Pete Flaherty in the general (Flaherty had won his primary by a majority, 53%, and among the primary candidates was former IA Congressman Ed Mezvinsky, who received 7%, and who had only been defeated by the ultra-RINO Jim Leach 4 years earlier and carpetbagged it over to PA, and he’s, of course, now in prison today).
Specter probably would’ve lost reelection in 1986 had the Democrats nominated a different candidate for the general. Specter faced a single opponent in the primary, Richard Stokes, who still managed to get 24% as a protest. Because the Marxist Castroite Congressman Bob Edgar (who represented the same district Sestak does) narrowly defeated former Congressman and State Auditor Don Bailey, who was considered a Social Conservative (overall a moderate, and who voted to the right of Specter in his last year in the House), 47-45%, Specter lucked out by having an opponent that made him look like Jesse Helms (and won, 57-43%).
The reason Edgar jumped in was because he was nearly beaten by Curt Weldon in ‘84 (winning by just 412 votes), and Weldon was expected to knock him off in ‘86, so he just opted out and decided to see if he could win statewide. It was similar to how the also-vulnerable Al D’Amato lucked out in NY by getting the moonbat Mark Green as his general opponent instead of Power Authority Chairman John Dyson. D’Amato had the mercilessly effective tv ads going until Election Day, so much so that if you asked a kid at the time living in the NY Media Market if he heard the name “Mark Green”, the kid would answer “Hopelessly Liberal !”