By not turning over a report Congress has requested, the White House is breaking the law and violating the separation of powers doctrine that underwrites America’s constitutional republic.

Days after Washington Post columnist Jamal Khashoggi was lured into the Saudi consulate in Istanbul, Turkey, and brutally murdered in an assassination plot hatched by the Saudi government, the top two lawmakers on the Senate Foreign Relations Committee wrote a letter to President Trump with a straightforward request: Identify any person who was involved in the crime and determine whether these individuals qualified for sanctions designations.

“Our expectation,” Sens. Bob Corker, R-Tenn., and Bob Menendez, D-N.J., said at the time, “is that in making your determination you will consider any relevant information, including with respect to the highest ranking officials in the Government of Saudi Arabia.”

Actually, the letter was more than a request. It was a requirement. Under the Global Magnitsky Act, the president is mandated to submit these determinations within 120 days of the chairman and ranking member asking for the information. The provision in the law is right there in black and white for any American who cares to look.

Evidently, the White House believes it can flout the law of the land and ignore any paper coming from Capitol Hill on this subject. The Trump administration is refusing to comply with the Magnitsky Act request, with a senior administration official telling CNN Friday that “[t]he President maintains his discretion to decline to act on congressional committee requests when appropriate.”

The White House will no doubt find some lawyer in the executive branch to write a memo justifying why shunning congressional requirements in the Magnitsky Act is perfectly legal and above board. Legal arguments will be trotted out to persuade at least some lawmakers that on national security policy, Congress can’t force the president to do anything he doesn’t want to do.

Whether lawmakers will sue the president for the information, or take matters into their own hands by passing any number of anti-Saudi bills now circulating in the Capitol, is a whole different issue. Bluntly put, the core problem right now is the fact that the administration is violating the statute in order to protect Saudi Crown Prince Mohammed bin Salman, a man who has proven over the years to be as dictatorial and reckless as he is ambitious, from being held accountable.

In truth, Congress doesn’t need a report from the president to figure out who ultimately ordered Khashoggi’s killing. The press reporting since the murder has pointed in the crown prince’s direction. The crown prince desperately wanted Khashoggi to stop writing about Saudi Arabia’s increasing despotism at home and destructive adventurism abroad. He talked with his senior aides about convincing the journalist to come back to Riyadh voluntarily — and if he wouldn’t, then to forcefully throw him on a plane back to the Kingdom.

This week, the New York Times reported on intercepts captured by the U.S. National Security Agency where the crown prince remarked that he would silence Khashoggi one way or the other, even “ with a bullet.” The United States already knows who the offender is. The CIA assessed a short period of time after Khashoggi’s slaying that the crown prince was culpable.

However, just because the intelligence community has made its judgment doesn’t mean the White House shouldn’t make its own. All Congress is asking for is for the president to hand over his conclusions. For the White House to disregard congressional mandates is an act of extreme disrespect to lawmakers who want to hold all Saudi officials accountable.

Congress is the policy-making branch of the U.S. government. But in order for lawmakers to craft good policy, they need cooperation from the executive branch and the most up-to-date information available. If Trump doesn’t relent, he is in effect blocking a coequal branch of government from doing its job.

Daniel DePetris (@DanDePetris) is a contributor to the Washington Examiner 's Beltway Confidential blog. His opinions are his own.