[quote][b]Posted by:[/b] westpointusma15 Yes The enemy soldiers would be breaking many laws including possessing automatic weapons, shooting in public areas, killing US citizens, and a huge many more. Also, police would be the first line of defense since they are already in charge of their Precincts. It requires the President to start Martial Law/a Congressional session to allow US troops to perform anything but training missions on US soil.[/quote]Although the US President has the US Marines which don't need congressional approval for military action. The Marines are technically a military branch serving as the President's world-wide quick action force. When it comes down to it they take their orders from the president. And I'm pretty sure that if hostile soldiers started walking on the US mainland (I'm American so just an example) and started trying to take over cities and actually invade then many with rifles will be out their fighting or protecting their family. In that case so will police and servicemen WILL be deployed first... congressional approval as it happens.