Forty-five years ago today, Congress sent the proposed 25th Amendment to the states for consideration and ratification. Although its framers recognized their work left some open issues, they constructively addressed the two most important gaps in the system of presidential continuity — presidential inability and vice presidential vacancy — by providing procedures to handle both problems.

[IMGCAP(1)]That old accomplishment raises the question of why Congress has not, for 45 years, returned to the subject to address the remaining gaps in our system of governmental continuity. The holes that remain are serious, and events since 1965 have provided notice that the system presents disasters waiting to happen.

Take the system of presidential succession. Current arrangements put the Speaker behind the president and vice president in line of presidential succession. For 62 percent of the time since 1965, the president and Speaker have come from opposing parties.

That arrangement could produce a change in party control of the White House if the presidency and vice presidency fell vacant at the same time. Ronald Reagan wins in a landslide, but Tip O’Neill acts as president; Bill Clinton is elected by a comfortable margin, but Newt Gingrich takes the helm.

But the specter of cross-party succession is only one deficiency in the succession system after the vice presidency.

The line of presidential succession includes 18 successors ranging from the vice president to the secretary of Homeland Security. They all work in Washington, D.C. It’s prudent to have a long line, but isn’t it conceivable that our nation’s enemies might target our nation’s capital? Think 9/11. Wouldn’t a little geographic diversity make sense in an age in which terrorists may possess nuclear weapons?

Former Vice President Dick Cheney was pilloried for working in “undisclosed locations” after 9/11. In fact, he deserved credit for being one of the few government officials to take these issues seriously.

The presidential succession law has other problems, but there are too many other gaps elsewhere to spend more time there.

Although the 25th Amendment provides a system to transfer power to a functioning vice president if the president is disabled, lawmakers have provided no means to handle presidential inability absent a vice president or when the vice president is incapacitated.

The presidential election system presents a host of unhappy contingencies that could recall Florida 2000. Suppose a presidential candidate dies, or a natural disaster or terrorist attack strikes, right before the November popular vote? Should voting or some of it be postponed or extended? Other complications occur if the presidential candidate who wins a majority of electoral votes dies before they are cast or counted or if the election for president or vice president is thrown into the House or Senate and one of the leading candidates dies.

The biggest gaps in our system, however, relate to Congress. Those problems might have become more evident on 9/11 had passengers on United Flight 93 not interceded to cause that plane to crash in southwestern Pennsylvania, 150 miles from the Capitol, which al-Qaida apparently intended as its destination.

Although governors of most states can appoint replacements to the Senate pending elections, open seats in the House require special elections, which typically take months.

Imagine an attack that killed or disabled much of the House. It could only conduct business if a quorum was present. Although House precedents define a quorum as a majority of Members who have been chosen, sworn and are living, some believe the Constitution requires a majority of the whole number of the House (i.e., 218 Members).

As the Continuity of Government Commission pointed out in its May 2003 report, either approach poses serious problems. If the House can act only when 218 assemble, a mass catastrophe would preclude it (and accordingly the government) from functioning.

Even if the quorum is based on living Members, the disability of many Members might preclude a majority of living Members from meeting and acting. And if the handful of survivors did act for the entire body, House actions might be subject to questions regarding their legitimacy, especially if the survivors were not representative of the whole.

There are solutions to each of these problems. The test for reform should not be whether they have shortcomings but how alternative arrangements compare to the status quo. The status quo is unacceptable, and its persistence is unconscionable.

The Congress that proposed the 25th Amendment constructively addressed two major problems because it recognized that perfection should not be the enemy of the good and struck compromises to better ensure governmental continuity.

After 45 years, it’s time for Congress to recall that lesson, and to act.

Joel K. Goldstein, the Vincent C. Immel professor at Saint Louis University Law School, is an expert on the vice presidency, the presidency and constitutional law.