Isn't Obama also the only president to win reelection with a lower share of the popular vote than his original election? I can't think of anyone else (not including FDR's third and fourth terms) without going back to pre-popular vote days (e.g., James Madison).
Wilson too, but yes those are the only two.
Wilson's share of the popular vote went up from 1912 to 1916. His margin of victory might have gone down but his share of popular vote went up. The only other person I can think of is Andrew Jackson. His popular vote % went down from 1828 to 1832 even though he won a greater share of the electoral vote from 1828 to 1832. [all this info are on this website given we are on "uselectionatlas.org"]
A better statement is: Obama also the only president to win his first reelection with a lower share of the popular vote AND a lower share of the electoral vote than his original election. [I used first to exclude FDR's 1940 and 1944 reelections.]
In fact I was so sure about this rule [A President either loses re-election or wins with a greater margin] that I was convinced Obama would lose in 2012 since it was clear he would lose ground in both popular and election vote. I guess we are in such a super-partisan environment that this rule no longer applies.
