I can imagine issuing letters of marque would be an act of war.
Wouldn’t put it past the imbeciles in DC to pass something like this due to the threat to their money laundering schemes in Ukraine. Giving no thought to what would happen if such a “bill” was passed. Typical political MSM/ DC insider created crisis, which the US should watch and stay out of it. But the politician can pass a bill to show their constituents they are doing something, no matter how unnecessary or ridiculous, without even thinking that the constituents know what’s going on.