Put these in order by moving the fewest names:

Washington, Wilson, Johnson, Johnson, McKinley, Davis, Jackson, Taft, Kennedy

Moving a name to between two other names, before the first name, or after the last name all count as one move. Thus, exchanging #2 and #7 requires two moves (since you'd have to move #2 and then move #7).

Note that "order" need not necessarily mean chronological order.

UPDATE: So far, no right answers ("right" = "the one I think is cool") in the first 11 posts, so I suppose this is a tough one. If you like this, please forward it to puzzle-loving friends (or discussion lists).

FURTHER UPDATE: Ed Johnson, in the comments, got it; Bob W almost got it.