WASHINGTON,D.C. -- As Capitol Hill erupted today with news that longtime Sen. Arlen Specter of Pennsylvania was changing parties, congressional Republicans rushed to control the damage — characterizing the switch as a fluke and warning about the dangers of a filibuster-proof majority that would be created in the Senate if Democrat Al Franken were ultimately seated.

“What this means, if we are not successful in Minnesota, as you know, is that the Democrats, at least on paper, will have 60 votes,” said Senate Minority Leader Mitch McConnell, R-Ky., during a news conference today. “I think the danger of that for the country is that there won’t automatically be an ability to restrain the excess that is typically associated with big majorities in a single-party rule.”

Specter, who has served in the Senate as a moderate Republican for almost 30 years, was expected to face an extremely tough primary in 2010.

“Since my election in 1980, as part of the Reagan Big Tent, the Republican Party has moved far to the right,” Specter said in a statement. “Last year, more than 200,000 Republicans in Pennsylvania changed their registration to become Democrats. I now find my political philosophy more in line with Democrats than Republicans.”

On Tuesday, Republican leadership painted Specter’s sentiment as a reflection of a uniquely Pennsylvanian situation, arguing that it did not suggest that the Republican Party was somehow out of step with the American people.

Sen. John Thune, R-S.D., said that he “regretted” Specter’s decision and called it “a little bit of a bombshell.”

“But, like I said, I think it reflected cold-blooded realism on his re-election prospects — nothing more, nothing less,” Thune said. “I think it is largely a Pennsylvania issue. We have not done well in Pennsylvania in the last two elections on the presidential level. … I don’t view it as any more of a broader commentary on the Republican Party. It is essentially a Pennsylvania story.”

On that note, McConnell said that Republican leadership had been aggressively supporting Specter for re-election as a Republican, and that his decision had nothing to do with how he had been treated by congressional Republicans.

“This is a Pennsylvania story about his inability, according to his pollster, to be re-nominated by the Republican Party, [or] to be elected as an Independent. And, so, he made a totally political decision … We [the Republicans] have a broad party. We have not done very well in the Northeast in the last couple of years… [But] I do not accept that we are becoming a regional party.”

Minnesota's 6th District Republican Rep. Michele Bachmann downplayed the signficance of the switch.

“On paper, this switch looks damning for Republicans, inching Democrats closer to their 60-vote filibuster-proof majority; but in reality, Senator Specter’s vote was already lost,” Bachmann said in a statement.  “Senator Specter’s decision today is all about politics -- about the politics of the Senate; about the politics of the Pennsylvania Republican primary.”

However, Norm Ornstein, a congressional expert and resident scholar at the conservative-leaning American Enterprise Institute, argued that the implications were potentially broader and more significant than the Republican Party was choosing to admit.

“Well, he [McConnell] may not accept it, but when you are down to no Republican House members in all of New England, and now two senators from Maine (your only Republicans in the entire region), and when you lose a House seat in a district that had a Republican edge in upstate New York, and then you have Specter — it is a pretty grim picture,” Ornstein said.

At the same time, party identification can be a fluid thing, depending largely on current events.

Republicans, in fact, maintained a slight edge over Democrats in the weeks following the terrorist attacks of Sept. 11, 2001, according to polls at the time. Over the next few years, that began to change as dissatisfaction grew with the war in Iraq and then the economy.

“There are going to be times when the public decides that the ‘in’ party needs to be punished,” Ornstein said.

Thune added that the people who are currently moving away from the Republican Party aren’t necessarily jumping in with the Democrats.

“They are moving into Independent range, which tells me that they are gettable,” Thune said. “And I think that if we, as the Republican Party, get our compass sort of set back straight we can move a lot of these folks back. … We [both the Republican and Democratic parties] are going to have to fight really hard to attract that block.”

Despite the party switch, Specter has also emphasized that he is “not an automatic 60th vote.”

For example, Specter said he would remain opposed to Card Check, a major labor issue.

Still, the Democrats are obviously happier to have Specter — even if he will not be an entirely reliable vote — on their side of the aisle.

Sen. Amy Klobuchar, D-Minn., called it “good news.”

“I think for a long time his heart has been leaning toward changing, and he is an independent guy. I think he is not going to go lockstep with us every step of the way, which is fine,” Klobuchar said.

On the implications for Minnesota’s open Senate seat and Democrats nearing the 60-seat majority, Klobuchar added these thoughts:

“The intensity of the fight [for the Senate seat] could increase. ... I hope not. I think it [the ongoing recount battle] should be decided on its own merits, according to Minnesota law.”

Fourth District Democratic Rep. Betty McCollum said that Minnesota had already “gone far too long with only one senator.”

“This is Minnesota’s senator; it isn’t the National Republican Party’s senator,” said McCollum.

“I expect Governor Pawlenty to look carefully at the [State Supreme] Court’s ruling, and if they rule the way I expect them to… I expect Gov. Pawlenty to put aside partisan politics and to put Minnesota first, and to make Minnesota 100 percent with two voting members of the U.S. Senate,” McCollum said.

On the other hand, if the State Supreme Court instead rules in favor of former Republican Sen. Norm Coleman, McCollum indicated that she might not want the governor to move so swiftly.

“If the court rules in Coleman’s favor, we will have to see what the options for that would be,” McCollum said, adding. “I don’t have a crystal ball in front of me but, quite frankly, I would be shocked.”

But, even if Franken is ultimately seated, Klobuchar said that as the Senate tackles issues as complicated as health care and energy the Democrats are not likely to be entirely in agreement on every aspect.

“I think that it won’t all be partisan — we may gain a few [votes], we may lose a few,” Klobuchar said.

“So, I think that it does increase the importance, but I think that some people may make it into Armageddon on the other side and I don’t see it that way. I never have.”

So, what do you think about Specter’s decision? Does his switch really say something larger about the Republican Party? Or is it, quite simply, a Pennsylvania story? Comment below.