Ron Barber, the longtime district director for Gabrielle Giffords' Congressional District 8 office, is expected to announce plans to enter the race to complete her term today. Details to follow, but for background, see this week's Skinny column:

As our print deadline closes in, it appears likely that Ron Barber, who has served as the district director for Giffords' congressional office since her election in 2006, will enter the race to finish out her term in Congressional District 8.

"I would be shocked if we didn't hear an announcement soon that Barber is running for the interim position," Pima County Democratic Party chairman Jeff Rogers told us earlier this week, adding that a Giffords endorsement would probably come along with the announcement.

Barber, 66, who was nearly killed after being shot twice on Jan. 8, is thought to be offering himself up as a caretaker for the remainder of Giffords' term, but multiple sources tell us he will not run for the new Congressional District 2 later this year.

Barber's entry will likely clear the Democratic field, with aspiring candidates now free to build campaigns to battle it out in the Democratic primary for that new CD 2 seat.

If that's how it plays out, Barber will face the winner of the April 17 GOP primary. Three Republicans—state Sen. Frank Antenori, 2010 GOP CD 8 nominee Jesse Kelly and businessman/sports-broadcaster/rugby-coach Dave Sitton—have already announced bids in that contest, and we hear that a fourth candidate, political newcomer Martha McSally, is likely to get into the race by the end of the week. (More on that later.)

Barber's entry complicates things for the GOP candidates: All but one of them will lose in the primary, and the winner will have spent plenty of campaign funds before pivoting to face Barber, who would have Giffords' backing and an enormous amount of goodwill among voters.

After the special election is decided on June 12, the Republican candidates will then have to decide whether to mount new campaigns for the regular election against Democratic candidates who have had the opportunity to build their campaign organizations in the new Congressional District 2, which covers much of the same territory as the current CD 8, but does not include GOP-heavy precincts in Marana, Oro Valley and SaddleBrooke.