DES MOINES  A deeply divided and partisan Congress comes close to forcing the country to default on financial obligations and only a last-minute legislative agreement stops that from happening.

Polls, such as one released Thursday by Pew Research Center, show anti-incumbent feeling at a historic high and dissatisfaction with government in general nearing all-time highs.

“Partisanship in Congress has increased dramatically, there’s no question about it,” said Chris Larimer, a political science professor at the University of Northern Iowa. “What you see over the long term in studies is less and less do you have people crossing party lines with their votes; everyone is voting more cohesively as a group.”

So what leads to that partisanship? One theory that gained steam during the shutdown is the creation of so-called “safe” congressional districts that reliably elect members from one party over the other every 10 years following the census. Not having to worry about challenges in the general election, lawmakers tend to tack to the extremes of party ideology to avoid a challenge in the primary.

For instance, a data crunch by the Cook Political Report released earlier this month found that during the last government shutdown in 1995, there were 105 congressional districts that could be considered “competitive” based on party registrations and voting patterns. In 2013, there are 53.

“That’s the theory,” said Keesha Gaskins, a senior counsel with New York University School of Law’s Brennan Center for Justice. “I think this (shutdown) revives some of the reform conversation; you probably have more centrists thinking about it.”

Whether that results in any action, Gaskins said, is a different matter.

In Iowa

Each state handles the drawing of political maps in their own way. In 34 states, legislatures have the primary responsibility for drawing maps. Seven states have independent commissions draw maps, and three states, Iowa included, have an independent agency draw lines. Other states have only one congressional district so they are not involved in drawing the lines.

“Every now and then, we have someone, or a group, call us about our process,” said Ed Cook, who heads the redistricting effort for Iowa’s Legislative Services Agency.

Every 10 years following the census, the nonpartisan agency redraws congressional, state Senate and state House districts.

In general, the process takes population into account first, followed by jurisdictional lines in drawing the district. The latter requirement is to mitigate the chances electoral districts splitting a county or a city into two or more parts.

Maps are delivered to the Legislature, which can accept them or reject them. If legislators reject them, another set of maps is delivered. If lawmakers reject that set, the Iowa Supreme Court gets to decide on the lines.

“In the 1970s, the plan went to the court,” Cook said. “That was the last time they let it go that far.”

Larimer, the UNI professor, studied the effects of the system. He found that in 27 of 38 elections from 1900 to 1972, when reform took place, five or more seats in the Legislature switched parties, about 70 percent. In the 20 elections from 1974 to 2013, only 10 had a five-or-more-seat switch, or 50 percent.

“I think it shows you got rid of these wild swings, that have a lot to do with ideology,” he said. “It has had a moderating effect.”

Although Cook said he gets people asking about Iowa’s system, he’s not aware of anyone picking it up whole hog. That’s likely because those most interested in reform tend to be ones out of power. Case in point, the last group to bend his ear was a club of Democrats from Wisconsin.

As Drake University Politics Professor Dennis Goldford put it, “There’s a vested interest by those in the majority to keep things the way they are.”

A problem?

Not that everyone sees a major correlation between district lines and the party line.

“Redistricting/gerrymandering is not the, or even a major cause of partisan polarization and the dysfunction in Washington,” Thomas Mann, author and W. Averell Harriman Chair at the Brookings Institution, wrote in an email. Mann’s research interests include redistricting, political polarization and campaign finance reform.

“I support nonpartisan redistricting process but don't see that as a route out of our problems,” he said.

He thinks there are systemic conflicts with party identity, among other issues, that cause partisan gridlock.

Goldford does, too.

“There’s a larger problem in that we have relatively weak political parties,” he said. “You’ve got no control over the party name.”

He said the reform movements of the 1970s that replaced the old slating committees with primary votes “opened it up for all sorts of groups to run under a party name.”

It also opened it up to money from outside groups — as opposed to in-party money — playing a much larger role in elections.

Even Gaskins said it’s hard to see a scenario in which the shutdown leads to end the gerrymandering.

“In California, you recently had a commission put in place that I think is working out,” she said. “But that came about because California has the proposition system to get these questions on the ballot much easier than in other places.”

Cook, however, wasn’t prepared to say he’s given his last Iowa redistricting talk.

“You never know when it’s going to come up,” he said.