The Senate is headed for a showdown over the filibuster. Democrats and Republicans are locked in a struggle that brings to mind the Cold War deterrence strategy of mutually assured destruction.

This theory held that the nuclear arsenals of the Soviet Union and the United States could each annihilate the other, so neither would dare launch an attack. Under Senate Rule 22, a two-thirds majority is needed to end debate and change the rules. Democrats are threatening to invoke the unprecedented claim that only a simple majority is required. They used to say the simple majority, or the "nuclear option," could be used only on the first day of a new Congress. They've dropped that nuance, asserting that it may be used at any moment. Majority Leader Harry Reid is counting votes.

Republicans, particularly with their efforts to block confirmation of President Obama's appointments to the U.S. Court of Appeals for the D.C. Circuit, are poking the Democrats with a sharp stick. Their obstruction of the confirmation of Richard Cordray as head of the Consumer Financial Protection Bureau is even less justifiable. Republicans don't even pretend to oppose the nominee; they hope to force changes to the agency, which was created by the 2010 Dodd-Frank financial reforms and which they do not like.

In short, Democrats' frustration is well-justified. But neither side is "right" or would "win" should Senate procedure be changed in this way.

For one thing, the nuclear option will no doubt lead to massive retaliation. Senate rules make the body extremely difficult to operate without some cooperation from the minority. And the GOP will someday again be in the majority.

In 2005, when Republicans were threatening to use the nuclear option and Democrats were outraged, then-Sen. Barack Obama declared, "One day Democrats will be in the majority again, and this rule change will be no fairer to a Republican minority than it is to a Democratic minority. … [W]e need to rise above an 'ends justify the means' mentality because we're here to answer to the people — all of the people — not just the ones wearing our party label."

Republican rage would be justified if Democrats change Senate rules by this means. During the 2005 confrontation, then-Sen. Joe Biden called the nuclear option "a lie about a rule," the ultimate "example of the arrogance of power" and a "fundamental power grab by the majority party."

The stakes here are far higher than tit-for-tat legislative warfare. Although the nuclear option would, at this time, be limited to nominations, its use would establish a precedent leading to majority control of the Senate. This would be true even if the ploy were limited to use on the first day of a new Congress; the outcome is exacerbated if any majority can change the rules at any time. The use of majority control would prove irresistible and the Senate would soon operate much like the House of Representatives, where the majority controls, the minority is seldom consulted, debate is limited and floor amendments often are not permitted.

This sort of showdown has flared up many times in the Senate. Eventually, compromise has always been reached. Experienced senators of both parties realize that this weapon would lead to the annihilation of the Senate as a body marked by negotiation, compromise and moderation.

In 1949, Lyndon Johnson, the "master of the Senate," said in defense of the filibuster: "If I should have the opportunity to send into the countries behind the Iron Curtain one freedom and only one … I would send to those nations the right of unlimited debate in their legislative chambers … If we now, in haste and irritation, shut off this freedom, we shall be cutting off the most vital safeguard which minorities possess against the tyranny of momentary majorities." Later, former senator George Mitchell told his colleagues that "when I was majority leader, I didn't always enjoy unlimited debate. There were times when I was frustrated by the ease with which the Senate rules can be used for obstruction. But with time and distance comes perspective … [t]he right of unlimited debate is a rare treasure which you must safeguard. Of course, it can be, and it is, abused. But that is the price that must be paid, and the privilege is worth the price."

Should the nuclear option be invoked, both parties will be mutually responsible: Republicans for their obstructionism and Democrats for their usurpation of power in the Senate. They will share the legacy of having undermined the Senate as it has been structured for more than 200 years.

Richard A. Arenberg, who worked on Senate and House staffs for 34 years, is coauthor of "Defending the Filibuster: The Soul of the Senate." He wrote this article for the Washington Post.