The humanitarian crisis unfolding in Yemen and the Saudi airstrike that killed 40 school children on a bus using an American-made missile suggests the Saudis aren't really trying to minimize civilian casualties, but Secretary of State Mike Pompeo recently certified that they are.
According to the Wall Street Journal, actual experts at the State Department told Pompeo he should not certify that Saudi Arabia is doing enough (because they aren't), but Pompeo sided with his legislative (read: political) advisers who said it would jeopardize the defense industry's pay-day.
The experts argued that certification would “provide no incentive for Saudi leadership to take our diplomatic messaging seriously,” and “damage the Department’s credibility with Congress,” according to portions of the memo shared with The Wall Street Journal.
They urged Mr. Pompeo to instead tell Congress that he couldn’t certify that the Gulf nations were doing enough to minimize civilian casualties, but that the U.S. would continue to provide military support to the coalition because it is in America’s national security interest.
[...]
The only group that urged him to fully support the Saudi-led coalition was the Bureau of Legislative Affairs, which argued in the memo that “lack of certification will negatively impact pending arms transfers.”
The State Department’s legislative team said “failure to certify may also negatively impact future foreign military sales and direct commercial sales to the region.”
This isn't just a matter of opinion; it's a matter of law.
Current law requires the State Department to certify that countries benefiting from American support have taken steps to minimize civilian casualties. If the State Department does not issue this certification every six months, support will be cut off.
If the Wall Street Journal's report is accurate, it would appear that Mike Pompeo is breaking the law by ignoring his own department's experts to issue certification.
I suppose you can add this to the increasingly-long list of things congressional Democrats can investigate if they regain control of Congress. Republicans sure as hell aren't going to.