J.D. Heyworth was a 6 term congressman, Jim Ryun had been in for 5 years, Nancy Johnson was on her 6th or 7th term, Curt Weldon had been in Congress forever, Anne Northrup had been there for years. Don't tell me that the GOP lost weak districts. They lost in what used to be some very safe seats.
Northrup had been in Congress for a long time, but all of her races had been very close and she had originally won in a seat that hadn't had a GOP representative in something like 150 years.
Ryun -- who had been elected in 1996 -- lost to an opponent whom he had beaten two years ago and who went out of her way to distance herself from the Democratic Party (she refused all DNC funds for her race). This is the kind of race Ryun could come back and win in two years.
Nancy Johnson originally won in the 6th District in CT back in 1982, but later became the 5th District representative when Connecticut's districts were re-aligned. Her seat was only "safe" in that the voters were content with a moderate who went out of her way to call herself "an independent voice in Washington." She was also one of the authors of the Medicare prescription drug plan in Congress, which pretty much tells me this wasn't a solid seat at all.
Weldon lost to a well-funded opponent (Joe Sestak) who ran a well-financed campaign, and who made his military background the major focus in what was arguably the most conservative Democratic campaign in the U.S. Weldon was also tainted by a whiff of scandal himself in recent weeks, which could not have helped him at all.