How did the United States end up without an ambassador to the most important non-nuclear nation in the world — Germany — for almost an entire year?

Even as Berlin and the entire country staggered from crisis to crisis in 2017, no senior representative of the United States was there to relay the president’s and the secretary of state’s views quietly to Chancellor Angela Merkel or loudly through the German press and official visits.

Richard Grenell, the former US spokesman at the United Nations and a sharp commentator on TV and Twitter, was nominated to be the US ambassador in Berlin in September and cleared committee in late October. But the new year opens without a US ambassador in Berlin, as there wasn’t enough time for a floor “debate” of 30 hours on Grenell in November or December.

It’s astonishing to neglect confirming any ambassador to an important ally, but Germany? That’s not only astonishing but also reckless in the extreme.

Whom to blame? Senate Democrats, of course. So much of the current confirmation crisis — scores of nominees are in Grenell’s boat, but his delay is one of the most risible and destructive — and its many consequences go back to the rule change they implemented.

When then-Senate Majority Leader Harry Reid (D-Nev.) employed a simple majority to change the Senate’s rules in November 2013 — the “Reid Rule” — he provided a path to change any rule the majority finds inconvenient. The Reid Rule was first employed by Reid to end the filibuster of all judicial and executive-branch nominees other than those of nominees to the Supreme Court — a result Democrats cheered.

But the consequences of deploying the Reid Rule were easy to foresee and much discussed at the time he used it. Other protections historically extended to the minority were sure to decline, and they have. The Republicans employed the rule to stop a filibuster of Neil Gorsuch’s nomination to the Supreme Court. For those of us who viewed the filibuster as constitutionally suspect (at best), this was welcome.

Now Senate Majority Leader Mitch McConnell (R-Ky.) is weighing using the Reid Rule again. Democrats, hoisted by their own petard, have responded to being in the minority in a Reid Rule world with the Senate version of college basketball’s long-ago-banned “four corners” offense where the game was slowed to a crawl by passing the ball endlessly to run out the clock.

The Democrats, led by Senate Minority Leader Charles Schumer of New York, are running out the clock on every nominee, demanding 30 hours of “debate” (of course, no one shows up to actually debate) in hopes that, come 2019, they will return to the majority. Then they can stop nominations the old-fashioned way — in committee, by a refusal of the majority party to bring the nominations forward.

Now a group of levelheaded senators led by James Lankford (R-Okla.) is trying to persuade colleagues to actually allow the Senate to do its job and dispatch certain to-be-confirmed nominees, like Grenell, to their jobs with much lower limits on the time their nominations can be debated on the floor.

If Lankford’s efforts fail, McConnell will have to choose between keeping the body in session around the clock (and many in the grass roots of the GOP are demanding that) or employing the Reid Rule again to effect another shattering of precedent.

Everywhere in the country, ordinary people marvel at the absurdity of the Senate and its inability to do anything on time even when led by McConnell, the most effective majority leader of my lifetime. Not having Grenell on post as the refugee crisis roils Germany, through discussions of NATO members’ dollar and manpower contributions and during the prolonged deadlock on forming a new government is the latest illustration of the damage Democrats have done and the scope of McConnell’s challenge.

National-security appointments were the last bastion of bipartisan civility. Now Democrats have tossed that aside, breaking what cannot be remade. The new year should begin with McConnell laying down the law on the basic duties of the Senate with another deployment of his predecessor’s rule.

Hugh Hewitt is author of “The Fourth Way: The Conservative Playbook for a Lasting GOP Majority.”

Special to The Washington Post