Robert Rees, the former conservative talk radio host who is challenging U.S. Senator Chuck Grassley for the Republican nomination, may not make it onto the primary ballot.

Bleeding Heartland covered Rees and his reasons for running against Grassley here. Launching a long-shot campaign two weeks before the Iowa caucuses wasn’t good for short-term publicity; journalists on the politics beat had so much other news to cover that few media reported on Rees’s campaign. But from an organizing standpoint, the timing was essential, because the Iowa caucuses provide an unparalleled opportunity to collect nominating signatures. A most precinct caucus locations, petitions for many candidates seeking state or federal offices are lying on a table for activists to sign.

To qualify for the June 7 primary ballot, Iowa candidates must submit enough valid signatures to the Secretary of State’s office by March 18.

This page on the Secretary of State’s website has a chart showing how many signatures candidates need in each county to count toward that ten-county minimum.

A February 22 e-mail blast from the Rees campaign to supporters included this appeal for help collecting signatures:

A quick fact-check on math: if Rees still needs to collect about 2,500 signatures, that means his campaign collected only about 800 valid signatures for his candidacy at the Iowa caucuses, roughly a quarter (not 1/3) of the 3,331 signatures he needs by March 18.

CLARIFICATION: Rees informed me that his campaign collected about 1,000 signatures on caucus night. He is (wisely) aiming for 2,500 more because he wants to submit more than the minimum number. The Secretary of State’s office recommends submitting more than the minimum, as a certain percentage of signatures on nominating petitions turn out to be invalid.

Keep in mind that more than 180,000 of the Republican Party’s most committed activists gathered at more than a thousand precinct caucuses on February 1. A well-organized campaign should have been able to collect enough nominating signatures that evening.

Rees now has just three and a half weeks to obtain about 2,500 signatures, and contrary to his e-mail, it’s not a simple matter of 100 supporters reaching out to 25 friends or neighbors. His petitions must have dozens or hundreds of signatures in each of at least ten Iowa counties to meet the threshold.

I’m not saying it can’t be done, but at this point Rees appears to be in real danger of not getting his name before Iowa Republican voters on June 7.

During the last election cycle, long-shot U.S. Senate candidate Paul Lunde held numerous campaign events in 2013 and early 2014 but failed to file nominating papers for the GOP primary ballot.

Any comments about the U.S. Senate race are welcome in this thread.