Under normal circumstances, political speeches should be judged on their content. And by this metric, Secretary of State Mike Pompeo’s remarks to the Republican National Convention were a mess.

The Kansas Republican claimed Donald Trump had strengthened NATO, which was the opposite of the truth. Pompeo insisted Trump’s failed policy toward North Korea was a success, which was pitifully untrue. The cabinet secretary said the president “held China accountable for covering up the China virus,” which was amusing, given Trump’s praise for China’s “transparency” on the matter.

Perhaps my personal favorite was Pompeo’s willingness to boast that Ukraine now has “defensive weapon systems” — systems Trump was impeached over after the president tried to leverage the supplies as part of an illegal extortion scheme.

But as important as these errors of fact and judgment were, the content of the secretary’s speech was only a small part of a much larger problem. NBC News reported late yesterday that the Republican’s convention speech is now under investigation on Capitol Hill — and for good reason.

The House Foreign Affairs Committee’s subpanel on oversight informed the State Department of the inquiry in a letter obtained by NBC News after the committee obtained internal State Department legal guidance that explicitly prohibited Senate-confirmed presidential appointees from even attending political conventions. The subcommittee’s chairman, Rep. Joaquin Castro, D-Texas, says that the speech is not only “highly unusual and likely unprecedented” but that “it appears that it may also be illegal.”

This doesn’t even seem to be in a murky gray area: federal ethics laws prevent the secretary of State from using his position — during a foreign diplomatic trip, no less — for partisan political purposes. Pompeo is supposed to be the chief diplomat of the United States, representing all of us in international affairs, not a GOP operative working on Trump’s re-election bid.

Indeed, Pompeo personally approved a State Department policy earlier this year that told the agency’s workforce, “Senate-confirmed Presidential appointees may not even attend a political party convention or convention-related event.”

He then proceeded to ignore his own policy, while simultaneously ignoring federal ethics laws and modern American norms. (The State Department has said Pompeo’s convention speech was delivered in his “personal capacity,” which is absurd on its face, and still at odds with his own agency’s policy, which allowed for no such exception.)

NBC News’ report added that the House panel investigating the apparent transgression is requesting a briefing by Tuesday, Sept. 1, “on how the speech came about, as well as a list of all costs related to the trip including those reimbursed by the RNC, the Trump campaign or others.”

Given the fact that Pompeo was speaking from Jerusalem — a not-so-subtle message to evangelical voters — it would also be interesting to know how much Israel’s government was forced to invest in order to provide security for the secretary’s political convention appearance.

To be sure, to know anything about Pompeo is to know that he prioritizes partisan politics above practically any other consideration, so his brazenness and indifference to institutional limits was in keeping with his general record. But against the backdrop of low expectations, the Kansan managed to stun much of the diplomatic community with his shameless antics.

“People are extraordinarily upset about it. This is really a bridge too far,” former Ambassador Linda Thomas-Greenfield, who spent 35 years in the foreign service, said this week. “Pompeo is clearly ensuring the State Department is politicized by using his position to carry out what is basically a partisan mission.”

For generations, secretaries of State from both parties knew not to do this. Some of the nation’s chief diplomats were better at the job than others, but each saw value in the office’s reputation and stature.

Pompeo has an entirely different set of priorities: simultaneously mixing campaign politics, religion, and U.S. diplomacy, all in the hopes of advancing his and his boss’ electoral ambitions.

I don’t know when Team Trump will leave office, but I know its successors will have a staggering mess to clean up.