Editor's note: David Frum, a CNN contributor, is a contributing editor at Newsweek and The Daily Beast. He is the author of eight books, including a new novel, "Patriots," and a post-election e-book, "Why Romney Lost." Frum was a special assistant to President George W. Bush from 2001 to 2002.
(CNN) -- Republicans face two decisions about the nomination of Chuck Hagel as secretary of defense: how to vote and whether to filibuster.
The vote decision should be easy: Nay, and for three reasons:
1) Hagel's history of contentious comments about the policies of the state of Israel is not merely obnoxious. That record will also severely impede his effectiveness in his portfolio. Israel is the United States' most capable strategic partner in the world's most turbulent region. Successful U.S. policy requires effective cooperation with Israel. In the 1990-91 Gulf War, Saddam Hussein attempted to wreck the U.S.-led alliance to rescue Kuwait by firing missiles at Israel. The United States asked Israel not to retaliate. This was an extraordinary and excruciating request. It's impossible to imagine the United States exercising similar restraint. Yet Israel complied.
Israel complied on that occasion -- and dozens of others -- because of the deep trust and respect between Israel and the United States. The Hagel nomination will strain that trust and complicate U.S. policy.
2) Hagel has put himself on record during the Bush administration, opposing a U.S. strike against Iranian nuclear facilities. It's not a problem that he thinks that way. It is a very big problem that he has spoken that way. Remember, the Obama administration insists that "all options are on the table" against Iran. It's important that the Iranians believe that. Appointing a secretary of defense who has already stated his opposition to the use of force severely corrodes the credibility of U.S. threats of force.
3) The next secretary of defense will preside over the steepest build-down of U.S. forces since the end of the Korean War. Reducing forces while preserving strength will present a daunting managerial challenge. Nothing in Hagel's career suggests he is equal to the task; and Hagel's underwhelming confirmation hearing strongly suggests he will not be equal to it. I can't remember any previous Cabinet appointee who handed in so dismaying a performance under senatorial questioning. Secretary of defense is too important a job for a man who has himself raised so many doubts about his basic competence.
Of course, the Democratic majority holds the votes to confirm Hagel even if Republicans unanimously vote "nay." The only way Republicans can stop the nomination is by filibuster. Should they? My answer to that is again: No.
The drift of the Senate away from majority rule to a new standard of 60-vote rule is a dangerous trend. It is especially dangerous in the context of presidential appointments. To allow 40 senators to block a Cabinet secretary is to move closer to the day when a minority of the Senate can altogether prevent the staffing of an administration. We've already moved ominously far in that direction.
Democrats filibustered President George W. Bush's nomination of John Bolton as U.N. ambassador. Although it's tempting to execute payback, it's better to lay down the rule for the benefit of the next Republican president: Presidents are entitled to staff their administrations with the people they want.
You may ask: But doesn't a "nay" vote by the minority accomplish nothing unless backed by a filibuster?
That question earns a third "No." The margin of a Senate confirmation vote sends a powerful message to the confirmed official. John Kerry's 97-0 confirmation as secretary of state empowers him.
A party-line vote on Hagel will restrain him. A party-line vote will demonstrate to the whole country Hagel's low standing with the Senate. Hagel will know that Congress is watching him distrustfully, that he will lack the authority and prestige of his other Cabinet colleagues, and that his first job in office must be to prove himself deserving of the job to which he was so grudgingly confirmed.
A party-line vote on the Hagel nomination will hold the president to account without paralyzing the administration. It's the right one-two response to this disappointing choice by a president who seems determined to use his second term to provoke and attack his opponents rather than to unite and lead the country.
Follow us on Twitter @CNNOpinion.
Join us on Facebook/CNNOpinion.
The opinions expressed in this commentary are solely those of David Frum.