The infamous history reaches all the way back to 1987, which is a long time when you're talking about a sitting United States Senator.  He is the Senior Senator from the Commonwealth of Pennsylvania, and he has played a primary role in the Senate's "advice and consent" on every nominee to the Supreme Court of the United States for nearly a quarter century.  If you're counting, that means this Distinguished Gentleman has had his say on eight of the nine current members of the highest court in the land -- every one but Justice John Paul Stevens, who was confirmed five years before the Senator became a member of the "world's greatest deliberative body."

The history began during the Senate Judiciary Committee hearings on the nomination of Judge Robert Bork to be an Associate Justice of the Supreme Court of the United States.  Everyone remembers that Judge Bork was vilified and caricatured by the Left from the day he was nominated up until the Senate rejected his appointment by a vote of 42-58.  But what conservatives remember is who among their ranks was not "with them."  That defector was Senator Arlen Specter.

Maybe Senator Specter's opposition to Judge Bork didn't seal his fate in the end.  After all, Judge Bork -- widely regarded as the foremost conservative legal scholar of his time -- was defined immediately by his opponents, most notably the leading liberal in the Senate both then and now, Edward Kennedy.  Backed by special interest groups, attack ads and the "mainstream" media, Senator Kennedy was able to make Americans believe that "Robert Bork's America" would be "a land in which women would be forced into back-alley abortions, blacks would sit at segregated lunch counters, rogue police could break down citizens' doors in midnight raids, schoolchildren could not be taught about evolution, writers and artists could be censored at the whim of government, and the doors of the federal courts would be shut on the fingers of millions of citizens."  In other words, the confirmation battle for Judge Bork was over even before it began, regardless of the unabashed slander.

Nevertheless, for conservatives, Senator Specter remains equally to blame for Judge Bork's defeat because the Senator "switched sides," turned his back on his President and his Party.

Fast forward four years and Senator Specter became the Right's reliable representative  when then-Judge Clarence Thomas became embroiled in his own Supreme Court confirmation battle after Anita Hill surfaced with her allegations of sexual harassment.  Through his cross-examinations of Ms. Hill, undermining her credibility in the eyes of many, Senator Specter may have saved Justice Thomas from being "Borked."  But, in doing so, for conservatives, Senator Specter had "switched sides" again.

Now, as Chairman of the Senate Judiciary Committee, Specter -- both the man and his unpredictability -- loom large over the impending confirmation hearings and proceedings for Judge Samuel Alito.

So which side is Senator Specter on now?  Well, it's just about anybody's guess.

A month ago, Senator Specter wrote in the Wall Street Journal: "Guarantees are for used cars and washing machines, not judicial nominees.  The backbone of judicial independence precludes any commitment on how a nominee will decide a specific case. ... If nominees are to be rejected through a speculative litmus test, it will be a sad day for the judicial confirmation process."  His words were a promising reassurance for conservatives, and seemed to be consistent with Senator Specter's more recent track record in supporting Justice Thomas and in ably controlling the Democrats during Chief Justice John Roberts' confirmation.

But just a month later, Senator Specter switched sides again by questioning Judge Alito on precisely what his op-ed promised should and would be off-limits -- how Judge Alito would decide cases if he was confirmed to sit on the Supreme Court.  Indeed, now Senator Specter was more than willing to ask the nominee virtually anything about judging on the High Court.

"What is your understanding of stare decisis and how should it guide a Supreme Court Justice? ... Do you agree with Chief Justice Rehnquist's view that cases should be upheld when they have become 'part of our national culture?' ... Are [cases such as] Mapp, Gideon, and Escobedo entitled to the same precedential weight as Miranda? ... Do you believe the Court should approach free exercise claims made by adherents of small minority faiths differently than it approaches claims made by adherents of more broadly subscribed to faiths?"  The questions went on and on.

So the Specter of switching sides has appeared yet again, playing brinksmanship with the Party, the President and, most importantly, what the Constitution establishes as a separate and independent branch of our government.  Let's hope Senator Specter got the message conveyed by conservatives before he took his seat as Judiciary Committee Chairman:  There are limits to forgiveness