Crossword Puzzle Hits a snag, with ''down''

Clue: Hits a snag, with ''down''

America's 39th President (CARTER with 6 letters)
Alma mater of the 39th Pres. (USNA with 4 letters)
It equals 0.3937 inch (CENTIMETER with 10 letters)
Super Bowl to be played in the year 3968, at the current rate (MMII with 4 letters)
39th VP (AGNEW with 5 letters)
39th vice president (AGNEW with 5 letters)
39th Veep (AGNEW with 5 letters)
39th V.P. (AGNEW with 5 letters)
Favorite Hall of Famer of the 39th U.S. president? (GARYCARTER with 10 letters)
39th president of the United States (JIMMYCARTER with 11 letters)