Mike Johnson’s Newest Headache: The Smallest House Majority in History

The Republican speaker held on to control of the House, but will preside over an even smaller majority at a time when President-elect Donald J. Trump will need his help to achieve major agenda items.

Speaker Mike Johnson’s small majority just got even smaller.

On Tuesday night, the final House race was called after Representative John Duarte of California, a freshman Republican, conceded to Adam Gray, a Democrat, cementing a 220-215 majority for Republicans in a margin even slimmer than they have now, at 220-213.

Those margins will erode even further in January, when Representatives Elise Stefanik of New York and Mike Waltz of Florida resign to take jobs in the Trump administration. Former Representative Matt Gaetz of Florida has also given notice that he will not return.

Republicans will then be down to a 217-215 majority, on par with the narrowest controlling margin in House history. If all Democrats are present and united in opposition to a measure, Mr. Johnson won’t be able to afford a single defection on the House floor until those vacancies are filled later this spring. Even then, no more than three Republicans can break ranks without dooming a bill’s passage.

Mr. Johnson sounded unfazed at the prospect on Wednesday, telling reporters on Capitol Hill: “We know how to work with a small majority. That’s our custom.”

He added: “We have nothing to spare. But all of our members know that. We talked about that today, as we do constantly — that this is a team effort, that we’ve got to all row in the same direction.”