On February 29, the Nebraska Secretary of State said he will place these names on presidential primary ballots:

Republican: Newt Gingrich, Ron Paul, Mitt Romney, Rick Santorum.
Democratic: President Obama.
Libertarian: Roger Gary, R. J. Harris, Gary Johnson, Carl Person, Bill Still, R. Lee Wrights.

Anyone who doesn’t wish to be listed may remove his name no later than March 10. Nebraska is one of the states in which state election officials place presidential candidates on the presidential primary ballot if the candidates are mentioned in news media. Candidates need not bother to apply.

According to this story, Maine Governor Paul LePage and Maine legislative leaders are seriously thinking of passing a bill quickly to postpone the March 15 primary filing date for candidates. As noted in the post below, the motivation is that Senator Olympia Snowe’s surprise declaration that she won’t run for re-election will make it difficult for new candidates to enter the race, with only two weeks for candidates to collect 2,000 signatures of party members. Thanks to Alex Hammer for the link.

On February 28, U.S. Senator Olympia Snowe of Maine said she will not run for re-election this year. The announcement was a surprise. Candidates in Maine face burdensome petitions to get themselves on primary ballots. Candidates for U.S. Senate need 2,000 signatures of party members, due March 15. This story explains that even Republicans and Democrats will have trouble with that, given the short time in which to get the signatures.

The story briefly mentions the idea that Americans Elect might run someone for U.S. Senate, but that is literally impossible, because no one can get on the Americans Elect primary ballot without 2,000 signatures of Americans Elect registrants, and Americans Elect doesn’t have that many registrants. The primary ballot access petition for Americans Elect ought to be considered unconstitutional, but only Americans Elect itself would have standing to challenge the 2,000-member requirement, and Americans Elect leaders say they don’t want any congressional nominees this year. Thanks to Rick Hasen for the link.

The Green Party is also ballot-qualified, but because primary ballot access for statewide office is so difficult in Maine, no Green has ever been able to get on the party primary ballot for either U.S. Senate or U.S. House.