More than half of the states in the U.S. are at "extreme risk" of congressional districts being drawn to unfairly favor one party, according to a new analysis of state redistricting processes by RepresentUs, a non-partisan advocacy group focused on election reform.

Why it matters: The states at risk of gerrymandering — a process the group says can produce "rigged maps" — include battlegrounds like Texas, Georgia, Wisconsin and North Carolina.

The big picture: This year's redistricting process is already more chaotic than usual. And the outcomes could boost one party's political candidates for a decade.

• "It's really just open season in a way that it never has been," RepresentUs CEO Josh Silver told Axios.
• That's due in large part to Supreme Court rulings since the last census that block partisan gerrymandering lawsuits from federal courts and ended requirements for some states to get their maps pre-cleared by the Justice Department.

What to watch: The U.S. is in a period of rapid demographic change, moving toward becoming a majority-minority population.

• "At the end of a 10-year [redistricting] cycle, the state can look very different than it did before," the lead researcher on the project, Jack Noland, told Axios. "That is all the more reason that we need fairer lines from the beginning, to sort of withstand those changes."

How it works: RepresentUs researchers looked at five key questions when determining each state's gerrymandering risk.

• Are elected officials or nonpartisan commissions are in charge of drawing maps?
• Can map-drawing can be done in secret?
• Does one party control the process?
• What are state criteria around how districts must be drawn?
• How hard it is to challenge gerrymandered maps in court?

"I think we have a good sense of where there is a prior history of gerrymandering in this country," Noland said. "But what we hadn't seen is an analysis of the laws on the books in these places."

By the numbers: 11 states saw high risk of gerrymandering across all five categories.

• Just seven states received a "minimal risk" rating: California, Colorado, Hawaii, Michigan, Arizona, Washington and Idaho.
• Democrat-run and Republican-run states alike fell into the highest-risk and lower-risk categories.

What they're saying: The report highlights the need for changes to the redistricting process in many states and advocates for a sweeping election overhaul bill Democrats passed in the House last month.

• Republicans have sharply criticized the bill, but Silver said given what’s at stake, it shouldn't be a partisan issue.

Go deeper:

• Gerrymandering is about to get even more chaotic
• Gerrymandering could take power from booming communities of color