CHICAGO (AP) — The U.S. Supreme Court refused Monday to hear an appeal from Illinois Republicans on newly drawn legislative boundaries, a move that state Democrats said affirmed that the map is fair.

The nation's high court gave no reason for declining. Senate Minority Leader Christine Radogno and House Minority Leader Tom Cross filed the appeal, claiming the Democrat-drawn lines were unfair to minority groups and GOP voters. Lower courts had thrown out their complaints.

"The court's ruling today is unfortunate and disappointing in light of the valid Voting Rights Act violations contained in the Democrats' legislative map," said a joint statement from Radogno and Cross. "We had voluminous studies by respected scholars to demonstrate our position, and they unfortunately will not get to be considered in a court of law."

Other Republicans — including Illinois Republican Party Chairman Pat Brady— said it wasn't surprising, since the high court doesn't hear too many cases.

Political boundaries for the U.S. House and state legislative districts are redrawn every decade based on new Census data. In Illinois, Democrats ran the process because they control the General Assembly and the governor's office. The new maps were signed into law last year, but have undergone several legal challenges.

Republicans objected to both the congressional and legislative maps, which they said drew Republicans out of their districts and lumped incumbent GOP members together or threw them into Democrat-friendly territory. Republicans also claimed that black and Latino voters had been shortchanged because the boundaries fractured ethic communities and weakened voting strength.

Challenges to the congressional map were heard by lower courts in Illinois, but ultimately failed.

Several U.S. representatives were affected by the new boundaries and chose to run in other districts to avoid challenging incumbents. It played out most clearly in Illinois' 16th District, where first-term U.S. Rep. Adam Kinzinger unseated longtime U.S. Rep. Don Manzullo in the March primary after switching districts.

The new map also reduces the number of congressional seats in Illinois — from 19 to 18 — because the state didn't grow as fast as others.

Democrats have defended both maps and said Monday that it was time to push forward.

The decision is "confirmation of what the Legislature and governor did a number of months ago," said Steve Brown, a spokesman for House Speaker Michael Madigan, who is head of the Democratic Party of Illinois.

"They met the requirements a number of months ago to put together a good solid redistricting plan," he said.