Courtesy of the Iowa Legislative Services Agency

The state is dropping from five districts to four districts due to slower-than-average population growth over the last decade, meaning that it was a foregone conclusion that two incumbents would be drawn into the same district.

But instead of making minor changes, the proposal is a wholesale re-drawing of the congressional map and pairs up two sets of incumbents, while leaving Rep. Leonard Boswell (D) in his own district and creating an open seat in the southeastern corner of the state – where the potential candidates include former Iowa first lady Christie Vilsack (D).

This map is not the final plan, however, as the state legislature and governor have to sign off on it first. Republicans, in particular, might bristle at the idea that Latham and King would be in the same district. Latham moved to his current home in Ames in 2001 to avoid just such a scenario.

Loebsack, meanwhile, is just a few miles away from the new open seat and could potentially run in that district – which contains much of the territory he has represented since 2006 – rather than running against Braley in a primary.

Democrats, meanwhile, will have three districts that went for President Obama in 2008, according to the Cook Political Report’s Dave Wasserman.

“I think there will be some strong Republican opposition to the map, not because the GOP would end up on short end of stick overall, but because King and Latham would really have to primary,” Wasserman said (check out his take here).

The map will now go to public hearings before being voted on by the state legislature, which can only vote “yes” or “no” and can’t make changes. From there, Republican Gov. Terry Branstad can veto the plan.

If the plan doesn’t pass muster, a second non-amendable plan will be introduced by the commission. If that doesn’t work, a third commission proposal can be amended by the state legislature. And if that fails, the state Supreme Court draws the map.

What that means is, effectively, either side can block a plan that it doesn’t like. Given that Republicans control the House and Democrats control the Senate, a compromise would have to be reached eventually. And if it can’t, the courts would take control.

It’s not clear how much friendlier a different plan could be, though. Iowa law requires counties to remain whole, which means there are a limited number of ways to draw the map. And turning down this plan means risking a future plan being even less friendly.

Historically, the legislature has agreed to the proposals relatively quickly. The process has not required a third proposal to be introduced since 1981.

Under the new plan, the state’s biggest population center, Des Moines, would move from the central 3rd district into the southwestern 3rd district. The district would remain very much a swing seat, but Boswell would gets an entirely new district, with Des Moines-based Polk County being the only county he gets to keep.

Braley’s northeastern 1st district would be largely intact, with its population bases remaining in Waterloo and Dubuque. But the district would lose Davenport and add Cedar Rapids-based Linn County, where Loebsack is from.

Besides losing Loebsack’s home, the southeastern 2nd district would add Davenport and much of Boswell’s old territory, while remaining based in Iowa City and Burlington.

The good news for Democrats is both of these seats would remain solidly Democratic as both went for Obama in the high 50s in 2008, according to Wasserman’s numbers.

King’s old 5th district, which currently includes the entire western third of the state, would give some of its southwestern territory – including Council Bluffs, across the river from Omaha, Neb. – to Boswell’s 3rd district. In exchange, it would take in the lion’s share of Latham’s north-central 4th district to form the new 4th district.

With so much of King’s and Latham’s territory in the same district now, there aren’t many good alternatives for either of them. Latham does not currently represent any territory in what would be in the new open 2nd district, and he represents only small pieces of the other districts. And while King could feasibly run against Boswell in the 3rd, that’s more of a swing district and would be tougher to hold in the long term.

For comparison’s sake, here’s the current map:

Courtesy of the Iowa Legislative Services Agency