Does Trump Have the Power to Block Spending That Congress Has Authorized?

President Trump has moved aggressively to block the government from disbursing funds authorized by Congress for a range of programs, potentially seizing power from the legislative branch to wield greater say in public spending.

Even as the White House cast the step as a temporary freeze that would allow it to inspect spending to make sure that it does not conflict with Mr. Trump’s policy priorities, the move set off chaos and uncertainty for vast swaths of the federal government at home and abroad.

It also appears to plant the seeds of a potential Supreme Court fight over how much power a president has to refuse to spend money that Congress has appropriated, a tactic that lawmakers sharply curtailed under President Richard Nixon.

Here is a closer look.

In his first week in office, Mr. Trump barred spending on certain initiatives whose mission he disagreed with, including programs involving “diversity, equity and inclusion” and funding to nongovernmental organizations he believes undermine the national interest. He also ordered a 90-day freeze on all foreign aid spending to review it for any conflicts with his priorities, making exceptions for military assistance to Israel and Egypt.

That freeze has jeopardized a broad swath of congressionally authorized aid, like military assistance to Ukraine in its fight against Russia’s invasion, helping pay the salaries of a Kurdish-led militia guarding Islamic State detainees in northeast Syria and the distribution of anti-H.I.V. medication in Africa and developing countries.

By the start of his second week, Mr. Trump signaled an escalation. On Monday, the White House, in a memo, ordered a temporary halt to “all federal financial assistance” like loans and grants on domestic soil as well. While Social Security and Medicare were exempted, the memo said it would apply to as much as $3 trillion in government programs and activities.

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