How broad is the president's power of amnesty?

[zachs2]

All the Constitution says is that they "shall have Power to grant Reprieves and Pardons for Offences against the United States, except in Cases of Impeachment." That seems very broad, but I want to clarify exactly how it works. If, for example, there were a president who decided that they wanted immigration reform or legal marijuana but Congress was stonewalling them, would they be able to just unilaterally declare an amnesty for all illegal immigrants or federal marijuana charges? If they did, would there be any possible legal recourse or is that amnesty just there to stay?

[brucejoel99]

Yes, if there were an unpopular federal law on the books that Congress refused to repeal (e.g., marijuana criminality), a President could literally just say "for the rest of my term, any person federally convicted of possession will be pardoned by me" & thus effectively negate the law (though this, of course, presumes that federal laws are the only laws criminalizing the given act), as the President's pardon power is extremely broad & has no real checks & balances on it: Congress could impeach them, but that'd take a pretty extreme abuse of power to actually trigger.

It's also happened before: Jimmy Carter pardoned everybody who dodged the draft in Vietnam.