Meanwhile, the post of secretary of the Army has been vacant since Nov. 1. Eric Fanning, who has had a swift rise at the Department of Defense, was nominated for the job in September. The Armed Services Committee didn’t schedule a hearing for him until January and waited until early March to vote in favor of the nomination. The full Senate has yet to schedule a confirmation vote. That has left the Army, which has a $140 billion yearly budget and more than one million soldiers, without a civilian leader with the authority to set priorities and address the needs of a force that has been at war since 2001.

At the State Department, Roberta Jacobson, one of the government’s foremost Latin America experts, has been waiting since last summer to be confirmed as ambassador to Mexico. The embassy, one of the largest in the world, has been without an ambassador since June. Ms. Jacobson, the assistant secretary of state for Western Hemisphere affairs, had a hearing before the Senate Foreign Relations Committee in July. The panel waited until November to approve her nomination, which the full Senate has not yet voted on. There are few diplomatic jobs more crucial than that of the ambassador to Mexico, who has to deal with border security initiatives, the influx of Central American immigrants and counternarcotics efforts. Ms. Jacobson is exceptionally qualified to tackle that long list of challenges and opportunities in Washington’s fraught relationship with Mexico, America’s third-largest trading partner.

Mr. McConnell could put an end to these inexcusable failures to conduct routine Senate business. But, of course, he and the rest of the Republican leaders long ago stopped doing anything in the interest of the country. Presidents Bill Clinton and George W. Bush got 528 and 545 officials confirmed during their last two years in office. Mr. Obama has managed to get only 193 nominees confirmed since early 2015.

Mr. McConnell and his colleagues are driven by a desire to retaliate against the administration when they have lost policy debates. So we have Senator Pat Roberts of Kansas holding Mr. Fanning’s nomination hostage over the administration’s efforts to shut down the prison at Guantánamo Bay. There’s Senator Marco Rubio petulantly blocking Ms. Jacobson’s appointment because she had a role in negotiating the change in relations with Cuba. And Mr. Szubin is being punished for the Iran nuclear deal.