Sen. Barack Obama said he would vote Monday to filibuster Judge Samuel Alito's confirmation to the Supreme Court, but he conceded the effort would be futile and criticized Democrats for failing to persuade Americans to take notice of the court's changing ideological face.

"The Democrats have to do a much better job in making their case on these issues," Obama (D-Ill.) said Sunday on ABC News' "This Week." "These last-minute efforts--using procedural maneuvers inside the Beltway--I think has been the wrong way of going about it."

Despite his criticism, Obama announced his intention to support the maneuver designed to block--or delay--Alito's confirmation this week. The movement, which was launched by Sen. John Kerry (D-Mass.), appeared to lack the 41 senators needed to be successful.

Alito, a federal appeals court judge, is poised to succeed retiring Justice Sandra Day O'Connor. The Senate is scheduled to cast a final vote on Alito's confirmation Tuesday.

The threat of a filibuster emerged late last week after liberal activists accused Democratic senators of failing to vigorously oppose Alito's ascension to the Supreme Court. After Kerry began the effort, several liberal groups mounted a campaign by Internet, telephone and fax to persuade other senators to follow suit.

"I will be supporting the filibuster because I think Judge Alito, in fact, is somebody who is contrary to core American values, not just liberal values," Obama said. "When you look at his decisions--in particular, during times of war--we need a court that is independent and is going to provide some check on the executive branch."

But in the next breath, Obama criticized the merits of a filibuster. The senator has worked to avoid being portrayed as walking in lock step with Democratic partisans, but at the same time he is seeking to be responsive to a core constituency.

"We need to recognize, because Judge Alito will be confirmed, that, if we're going to oppose a nominee that we've got to persuade the American people that, in fact, their values are at stake," Obama said. "And frankly, I'm not sure that we've successfully done that."

Kerry, who worked through the weekend to get other Democratic senators to join the filibuster effort, welcomed Obama aboard and praised him for "taking a stand on principle."

"It's not easy, but it's important for our country," Kerry said in a statement.

In his television appearance, Obama did not reconcile his views over the filibuster. Spokesman Robert Gibbs denied a Tribune request Sunday to interview Obama but said the senator decided to join the filibuster effort because he believes Alito "would be a bad addition to the Supreme Court."

Senate Minority Leader Harry Reid (D-Nev.) has argued against a filibuster. Other Democrats said the effort could allow Republicans to portray Democrats as obstructionist.

A filibuster, a procedural move to keep debate alive, could delay a final vote on Alito. If the filibuster attempt fails Monday, a vote on Alito's confirmation is scheduled for Tuesday, hours before President Bush delivers his State of the Union address. At least three Democrats and virtually all Republicans have pledged to support Alito, making his confirmation all but certain.

Sen. Joseph Biden (D-Del.) said he also would vote to keep debate open Monday, but he questioned the wisdom of a filibuster, predicting it would fail.

"I think a filibuster makes sense when you have a prospect of actually succeeding," Biden said Sunday on CNN's "Late Edition."

----------

jzeleny@tribune.com