Although both sides in the latest Trump-Pelosi kerfuffle are acting like juveniles, the president’s action in canceling the speaker’s trip to Afghanistan is a worse offense. It actually does interfere with significant government business.

Yes, Speaker Nancy Pelosi, D-Calif., began this latest spectacle by saying she might (hypothetically) rescind President Trump’s invitation to appear before Congress for a State of the Union address. Her reasoning was specious and petty. But as my colleague Philip Klein quite ably argued, it would be a blessed relief to end the “meaningless political spectacle” of the SOTU and instead have the president deliver his report in writing — or, if he wants to speak, to do so from the Oval Office.

The public weal would be in no sense harmed if presidents made that a new tradition. Indeed, it might be helped, because SOTU preparations effectively eat up a full legislative day from a Congress that quite arguably holds too few days in session already. For those actually trying to get work done on Capitol Hill, the SOTU address is an annoying and at least somewhat burdensome distraction.

The trip to Afghanistan that Pelosi and other House leaders were within a half-hour of embarking on, however, is a real and serious part of Congress’ business. The extraordinarily petty presidential letter canceling the trip called it a “public relations event.” That’s deeply unfair.

Congress is a coequal branch of government. Congress must decide whether to finance military excursions, decide what armaments to authorize, and weigh in on policies governing troop use, benefits, and conditions. A trip to a war zone is far from a junket. It requires a lot of preparation; it almost always provides important information to members of Congress and key staff that they just could not fully appreciate from 7,000 miles away; and it involves long work hours and some risk. Just about anyone who has worked on Capitol Hill has seen firsthand from returning members and staff just how eye-opening an experience those trips can be and just how much more focused the subsequent legislative and oversight efforts are.

For those reasons and others, these CODEL trips, short for “congressional delegation,” are usually carried out by military transport, with military organization. The president, as commander in chief, should want leading congressmen to take such trips. And the perfect time to take them is in January of a new term, when little other legislative business is being conducted and when a new legislative year brings the need to reassess policies and missions.

A trip like this is especially important for the speaker of the house, third in line to the presidency. Set aside the particular personality or ideology of Pelosi, and consider the office she holds. Of course she should take occasional CODELs to war zones and to meet with foreign leaders. Far from being a “public relations event,” it is highly legitimate business — and far more important than a staged and stale presidential address for which half the audience applauds every inanity and the other half refuses to acknowledge elements of real presidential grace or decency.

When Trump canceled Pelosi’s trip, especially right at the last minute, he vitiated the work and planning of hundreds of people, harmed our standing with foreign leaders with whom Pelosi was to meet, and arguably harmed the public interest. That’s not how a commander in chief should act.