The reason why Trump can’t start a trade war without causing a major financial crisis is the same reason why Biden and others won’t eliminate swift.

The structure of the current global monetary system is such that the US has to become a net exporter of dollars in order to create enough global liquidity for trade , but as a result, all these dollar surpluses build up in other countries that produce goods that are shipped to the US

These countries want to earn a yield on their dollar holdings so they reinvest the dollars back into US equities and US treasuries, which drives up stock price prices in the US and suppresses yields, which allows for more government borrowing.

Anytime you stop this process you immediately cause equities to sell off and bond yields to spike, which results in lower tax receipts from capital gains and higher interest expense.

The US cannot unwind global reserve currency status without disastrous consequences