Comment by Terr_

> they implicitly expect

Sure, but crucially "expect some" is not "expect all". The presence of some X is not the same as absolutely zero limitations on X.

Suppose the Federal government chooses to award a letter of Marque and Reprisal to... Bob. However, Bob is in State prison for life, because he was convicted of multiple murders, boat-theft, ramming boats into other boats, selling guns for drugs, whatever.

This sets up a State/Federal conflict, with four major types of resolution:

1. [Specific, State] The Federal government chose a useless agent, but that's their problem for making a stupid choice instead of picking someone not in prison who can wave a gun around and do the job they want done.

2. [Specific, Federal] A lawsuit occurs and it is decided the State has to specifically release Bob from prison and wave a gun around as long as he has that special Federal status.

3. [General, State] The Federal government loses all ability to deputize people because that could potentially cause a conflict.

[General, Federal] The State government loses all ability to imprison anyone or control anybody's gun-waving, because that could potentially cause a conflict.

Surely you'd agree that #4 (and #3) would be insane? Nobody drafted or ratified that M&R clause thinking that they agreed to nullify their State's ability to imprison, nor that the M&R clause itself would be dead on arrival. (Aside, #2 is problematic since it would give Congress a secret pardoning power even more-powerful than the President's.)