Not to be lost in the reporting on Tuesday’s Senate Judiciary Committee vote to endorse the nomination of Judge Samuel Alito to serve on the Supreme Court is the fact that U.S. Sen. Russ Feingold, D-Wisconsin, has voted for the first time in his Senate career against a Supreme Court nominee.

More than any other vote by a member of the committee — which split 10-8 along partisan lines, with all Republicans backing Alito and all Democrats opposing his nomination — Feingold’s vote stands out.

While the seven other Democrats on the Judiciary Committee had all voted against one or more Republican nominees for the high court, Feingold had, until Tuesday, voted to confirm every Supreme Court nominee, Republican or Democrat, to come before the panel.

This break in pattern by the man who is arguably the Senate’s most adventurous thinker and independent player ought to serve as a basis for rethinking strategies with regard to blocking the nomination as it now moves to the full Senate — up to and including the prospect of a filibuster.

Simply put, if Alito is unacceptable to Feingold, then he should be unacceptable to a good many other senators — including moderate Republicans with whom Feingold has worked closely on campaign finance reform and a host of other issues over the years, such as Maine Senators Olympia Snowe and Susan Collins and Rhode Island Senator Lincoln Chafee.

Why give this special status to Feingold? Because, since his arrival in the Senate in 1993, he has distinguished himself by his consistent if often controversial approach to presidential nominations.

The senator from Wisconsin has a record of supporting disputed Republican picks for top posts — including former Attorney General John Ashcroft and Supreme Court Chief Justice John Roberts — because of his belief that presidents should be afforded broad leeway when it comes to making appointments. A progressive who is perhaps best known for casting the sole Senate vote against the Patriot Act in 2001, Feingold has long argued that Democrats must support the qualified conservative nominees of Republican presidents if they expect Republicans to support the qualified liberal nominees of Democratic presidents.

Feingold’s standard has often infuriated liberal interest groups, along with many of his fellow Democrats, who have argued that he has given too much slack to right-wing Republicans who will never repay the favor. Why, the common question goes, does a progressive Democrat give conservative Republicans a blank check?

But Feingold has always rejected the “blank-check” analogy. The senator has voted against a number of federal appeals court nominees in recent years, and he has consistently made it clear that would oppose a Supreme Court nominee in an instance where a president selected someone who was too extreme, too biased or too ethically challenged.

The fact that Alito is the first high court nominee to fail to meet the Feingold standard is significant. And, as the senator explained to the committee Tuesday, it was not a close call.

In an unusually blunt statement, Feingold went out of his way to distinguish the current nominee from the Republican who he backed just a few months ago to serve as the court’s chief justice. “Judge Alito’s record and testimony do not give me the same comfort I had with Chief Justice Roberts,” said Feingold, who explained that, “Judge Alito’s record and his testimony have led me to conclude that his impulse to defer to the executive branch would make him a dangerous addition to the Supreme Court at a time when cases involving executive overreaching in the name of fighting terrorism are likely to be such an important part of the Court’s work.”

The three-term senator from Wisconsin who is being boomed as a potential progressive candidate for the 2008 Democratic presidential nomination pointed out that, on this most vital of issues, Alito’s record ought to be troubling to anyone — no matter what their partisan label — who respects the system of checks and balances that is outlined in the Constitution and that has served as a bullwark of American liberty over the past 218 years.

“Judge Alito has an impressive background and a very capable legal mind, but I have grave concerns about how he would rule on cases involving the application of the Bill of Rights in a time of war. Some of the most important cases that the Supreme Court will consider in the coming years will involve the government’s conduct of the fight against terrorism. It is critical that we have a strong and independent Supreme Court to evaluate these issues and to safeguard the rights and freedoms of Americans in the face of enormous pressures,” explained Feingold.

“Confronted with an executive branch that has jealously claimed every possible authority that it can, and then some, the Supreme Court must continue to assert its constitutional role as a critical check on executive power. Just how “critical” that check is has been made clear over the past few weeks, as Americans have learned that the President thinks his executive power permits him to violate explicit criminal statutes by spying on Americans without a court order,” Feingold continued. “With the executive and the legislature at loggerheads, we may well need the Supreme Court to have the final word in this matter. In times of constitutional crisis, the Supreme Court can tell the executive it has gone too far, and require it to obey the law. Yet Judge Alito’s record and testimony strongly suggest that he would do what he has done for much of his 15 years on the bench: defer to the executive branch in case after case at the expense of individual rights.”