The only way a mandatory check would work would be if the government could track every one of the 300 million firearms in the United States. And then the criminals would ask permission before buying them.
Emily Gets Her Gun: …But Obama Wants to Take Yours
[300 million guns? We have computers that could do that, right? They built a computer system that signed people up for Obamacare so they should be able to do that for gun owners, right?*
These would be necessary, but not sufficient, conditions for “universal background check to work”.
They would also have to shut off the smugglers. You should assume this would work about as well as the War on Drugs has worked.
They would also have to prevent all the 3-D printers from making new guns. You should assume this would work about as well as the peeing into the wind.—Joe]
*In fact the Canadian gun registry (disbanded after costing 2 billion rather than 2 million) was built by the same people that wrote the Obamacare website.