[Verginius Rufus]

Reagan would have been the third president to win all the states—after George Washington and James Monroe. Of course there were a lot fewer states back then.

[Vigilanteman]

In Washinton's and Monroe's time, presidential electors were not chosen by direct popular vote in the states either. They were chosen by state legislatures.

Also, even the 24 state re-election sweep by James Monroe in 1820 wasn't unanimous-- one New Hampshire elector voted for John Q. Adams and three electors abstained (Mississippi, Tennessee and Pennsylvania).

The very next election cycle (1824) was the first time that elector selection was made by direct popular vote and even then, it didn't become the only method until 1864.