When so many states decreased the legal drinking age from 21 in the 1970's, what caused them to increase it back up in the end?

by dancingbanana123

As I understand it, it was decreased because of the logic that if you're old enough to join the military, you're old enough to drink alcohol. What caused so many states to bring it back up to 21 after they changed it? Was there some big push for it to be increased or was there a lot of backlash over it?

youngandsavage

As a state you can't get federal funding for highways if your drinking age is lower than 21