TOP OF THE BALLOT TODAY: A three-way tie in Hawaii; Romney and Obama hit the campaign trail; Dems line up Isakson challenger in Georgia, just in case.

Toss-up in Hawaii

There's essentially a three-way toss-up in the May 22nd Hawaii special election.

The liberal website Daily Kos released a Research 2000 poll over the weekend. It showed Republican Honolulu City Councilman Charles Djou leading the way at 32 percent, while former Rep. Ed Case (D-Hawaii) and state Senate President Colleen Hanabusa (D) were close behind at 29 percent and 28 percent, respectively.

Case got a big boost on Sunday, when the Honolulu Advertiser endorsed him. But unless that endorsement helps him steal support from Djou, it may only cut up the Democratic equation even more.

What’s interesting here is that Case enters the race with significantly better favorable numbers (47 percent positive, 25 percent negative) than Hanabusa (37 percent positive, 31 percent negative). Djou (40 and 27) is somewhere in between.

Romney for Rubio; Barack for Boxer

A couple of big-name Senate candidates are getting some even bigger-name help today, with President Obama raising money for Sen. Barbara Boxer (D-Calif.) and Mitt Romney doing an event with former Florida state House Speaker Marco Rubio (R).

Obama joins Boxer as she finds herself in what is looking to be her most difficult reelection race yet, while Romney is a little on the late side in jumping on the Rubio bandwagon (especially now that it appears Gov. Charlie Crist is considering an independent bid instead of running in the GOP primary).

Still, the high-profile visits would have been nearly unthinkable a year ago, when Boxer’s challenge was still hypothetical and Crist looked like a future GOP presidential candidate.

Isakson challenger emerges

Sen. Johnny Isakson’s (R-Ga.) recent health problems have spurred Democrats to field a challenger in that race, and they got a good one.

State Labor Commissioner Michael Thurmond, who is one of just two Democrats elected to statewide office in the state, is expected to join the race Tuesday.

It’s hard to see the Democrats going after Isakson hard – he showed a 53-26 lead on Thurmond in a recent Daily Kos poll – but his candidacy forces Republicans and Isakson to reevaluate themselves and puts Democrats in a position to take advantage if, for whatever reason, Isakson isn’t able to campaign.

Other updates

-Former health insurance executive Charlie Baker, the party favorite, won an overwhelming victory over former independent candidate Christy Mihos at the Massachusetts Republican Party convention, forcing Mihos from the race to face Gov. Deval Patrick (D).

-Rep. Jane Harman (D-Calif.) survived her own convention scare, defeating activist Marcy Winograd (D) 599-417 and winning her party's endorsement in their primary.