The United States will lose one its best UN ambassadors when John Bolton leaves his post in Turtle Bay at the end of the year. But don't blame Democrats for Bolton's resignation. A handful of Republicans -- and a White House without a backbone -- are at fault for Bolton's departure.

There's no question Democrats played a role in blocking Bolton, but when he was nominated for the UN job on March 7, 2005, Republicans had a Senate with 55 Republicans, Bush was still very much in control of the agenda following his re-election triumph the previous November and the UN was in desperate need of reform in the wake of the oil-for-food scandal.

Despite those factors working in Bolton's favor, the GOP dropped the ball. And once it started rolling, they could never regain control.

Senate Foreign Relations Chairman Richard Lugar (R.-Ind.) may have publicly backed Bolton, but his inability to keep the committee in line prior to a vote set Bolton up for a humiliating defeat. Lugar's failure to recognize -- and address -- Sen. George Voinovich's (R.-Ohio) unease about Bolton handed Democrats what they needed: a Republican who objected to Bolton.

When the Senate, hamstrung by Voinovich, failed to act, President Bush was left with one option: a recess appointment for Bolton. During his time at the UN, Bolton proved his critics wrong. He won widespread praise, and this past July, even Voinovich changed his tune on Bolton, promising to vote for him.

When liberal Sen. Chuck Schumer (D.-N.Y.) signaled he was ready to vote against a filibuster of Bolton, it appeared the once-embattled Bolton would finally have the Senate's backing.

Except another misguided Republican chose to do the unthinkable. On the eve of the Republican primary in Rhode Island, liberal Republican Sen. Lincoln Chafee chose to stage a protest, vowing to oppose Bolton because he didn't agree with the U.S. policy in the Middle East. At the time, it looked like an election move to win over independents.

Sen. Liddy Dole (R.-N.C.), then-chairwoman of the National Republican Senatorial Committee, instead of pulling Chafee's funds to send him a message, decided to send money and staff to Rhode Island to save Chafee. It worked. On September 12, Chafee defeated conservative challenger Steve Laffey. The resources Dole provided were the boost he needed down the stretch.

What did Dole and the GOP get for their investment? Chafee refused to change his stance on Bolton, and even after losing on November 7 to Democrat Sheldon Whitehouse, Chafee remained adamant that he would continue to oppose Bolton's confirmation.

Lugar, Voinovich, Dole and Chafee aren't the only ones to blame for this mess. Bush and his congressional liaison team failed to accomplish what should have been a simple mission. Now, with Bolton having no hope for winning confirmation, the GOP has surrendered. Bolton, meanwhile, will end his tenure at the UN early, and the agency he sought to reform is left without the reformer it so desperately needs.

UPDATE -- 1:55 p.m.: The White House apparently wants no part of the blame for Bolton's resignation. President Bush's statement singles out "a handful of United States Senators" that we can only assume includes some of the names I mentioned earlier.

It is with deep regret that I accept John Bolton’s decision to end his service in the Administration as Permanent Representative of the United States to the United Nations when his commission expires.

Over a year ago, I appointed Ambassador Bolton because I knew he would represent America’s values and effectively confront difficult problems at the United Nations. He served his country with extraordinary dedication and skill, assembling coalitions that addressed some of the most consequential issues facing the international community. During his tenure, he articulately advocated the positions and values of the United States and advanced the expansion of democracy and liberty.

Ambassador Bolton led the successful negotiations that resulted in unanimous Security Council resolutions regarding North Korea's military and nuclear activities. He built consensus among our allies on the need for Iran to suspend the enrichment and reprocessing of uranium. His efforts to promote the cause of peace in Darfur resulted in a peacekeeping commitment by the United Nations. He made the case for United Nations reform because he cares about the institution, and wants it to become more credible and effective.

I am deeply disappointed that a handful of United States Senators prevented Ambassador Bolton from receiving the up or down vote he deserved in the Senate. They chose to obstruct his confirmation, even though he enjoys majority support in the Senate, and even though their tactics will disrupt our diplomatic work at a sensitive and important time. This stubborn obstructionism ill serves our country, and discourages men and women of talent from serving their Nation.

I thank John Bolton for the dedication and skill with which he performed his duties, and his wife Gretchen and daughter Jennifer Sarah for their support as Ambassador Bolton served his country. All Americans owe John Bolton their gratitude for a job well done