Nader, 73, has run for president as a write-in candidate on both the Democratic and Republican tickets in the New Hampshire primary 1992 as a "none of the above" candidate. He mounted more serious campaigns in 1996, 2000, and 2004.
Many Democrats resent his 2000 run, believing he sapped enough votes from then-Vice President Al Gore to hand the presidency to then-Gov. George W. Bush. In Florida, where Gore ultimately lost to Bush by 537 votes, more than 97,000 Floridians supported Nader, then on the Green Party ticket. Not everyone concedes that Nadar's candidacy in 2000 caused Bush to win.
Personally, I think that Ralph Nadar is simply a person who likes to see his name in print. I don't sense that there is a groundswell of support for Nadar. Quite frankly, I think that Ralph Nadar is lonely and wants some attention. The last time that Ralph Nadar was relevant was over 40 years ago when his book led to the failure of the Chevy Corvair.