They can try….
Check it out:

Missouri senators endorsed legislation on Tuesday that seeks to nullify U.S. gun restrictions and send federal agents to jail for enforcing such laws, though the measure would likely face a court challenge if it gets approved in the state.

Courts have consistently ruled that states cannot nullify federal laws, but that hasn’t stopped Missouri and other states from trying.

Sen. Brian Nieves, the Republican sponsoring the bill, said the legislation would protect law-abiding gun owners from federal encroachments and regulations. Missouri Republicans began pushing for the legislation following President Obama’s call last year for increased background checks and a ban on assault weapons.

The legislation would subject federal agents to civil and criminal penalties for knowingly enforcing federal gun laws. Agents could face up to one year in prison and a $1,000 fine.