The US Supreme Court has handed President Donald Trump three significant legal defeats in a single day, blocking his administration's efforts to remove Federal Reserve Governor Lisa Cook, restricting mail-in voting procedures, and dismissing a sexual harassment lawsuit brought by a writer.

The ruling on Lisa Cook is the most consequential for financial markets.

By rejecting the White House's attempt to oust the Fed governor, the high court has delivered a decisive blow to the administration's strategy of asserting direct political control over the central bank.

The decision reinforces the statutory independence of the Federal Reserve, a cornerstone of US monetary policy that markets rely on for predictable interest rate decisions.

In the other two cases, the court ruled against the administration on procedural grounds regarding mail-in voting and dismissed the harassment claim, further limiting the executive branch's legal maneuvering room.

These outcomes suggest a judiciary that remains resistant to the administration's broader efforts to reshape institutional norms.