Actually using import taxes – tariffs – to finance a big chunk of the federal government would be a painful and perilous undertaking, budget wonks say.

U.S. President Donald Trump is not interested in talking with Elon Musk, a White House official said on Friday, signaling the president and his former ally might not resolve their feud over a sweeping tax-cut bill any time soon.

The president cited figures from the Congressional Budget Office to suggest tariffs could offset the cost of tax cuts, though he omitted important caveats for why that may not be the case.