Richard Wolf

USA TODAY

WASHINGTON — President Obama has been unable to fill a seat on the Supreme Court for six months, but his lower court appointments could help swing the presidential election to his chosen successor.

Judges named by Obama to federal appellate and district courts overseeing North Carolina, Texas, Michigan and Wisconsin have in recent months voted to strike down restrictions on voting imposed by Republican legislatures. In Michigan and North Carolina, his Supreme Court nominees helped block efforts to restore the restrictions for this fall's elections.

The rulings could help hundreds of thousands of voters — mostly minorities who vote Democratic — get to the polls in November by removing impediments such as photo IDs and making it easier to register and vote.

"These decisions certainly demonstrate the critical importance of having a Democrat in the White House," says Nan Aron, president of the liberal Alliance for Justice. “These laws are transparent in intent, to harass and suppress the vote in states across the country.”

In states where Obama's judges have had less influence in voting rights cases — such as Ohio and Virginia — courts have left restrictions on voting in place.

The legal skirmishes, still playing out in many states, will have far more influence in deciding who wins the White House than the public opinion polls that command far more attention. They will determine the rules for the election in key battleground states, along with others far from the presidential candidates' radar, such as Kansas and North Dakota.

Courts may play pivotal role on voting rights in 2016 election

Civil rights groups fighting the state laws in court say their winning record stems from proving that photo ID laws and other limits discriminate — sometimes intentionally — against minority voters.

“I don’t think this can be attributed to the fact that Obama’s been appointing judges for the last seven and a half years,” says Dale Ho, director of the American Civil Liberties Union's voting rights project.

But Nicholas Stephanopoulos, an assistant professor of law at the University of Chicago Law School specializing in elections and voting rights, says judges tend to view the cases "through ideological and partisan prisms."

At the federal appeals court level, those prisms have shifted left since Obama came to office. While only one federal circuit court had a majority of judges named by Democratic presidents in January 2009, nine do now. The percentage of appellate judges named by Democrats has risen from 39% to 55% during that period.

So far this year, judges nominated by Obama and Bill Clinton have sided with civil rights groups and Democratic lawyers every time. Those named by Republican presidents Ronald Reagan, George H.W. Bush and George W. Bush have split their votes.

In North Carolina, the nation's most far-reaching set of voting restrictions was upheld by a Republican-named district court judge before being struck down by a three-judge, all-Democratic panel of the U.S. Court of Appeals for the 4th Circuit. That court had four judges appointed by Democrats when Obama came to office in 2009; it now has nine.

In Texas, a district court judge named by Obama struck down the country's strictest photo ID law. The customarily conservative 5th Circuit Court of Appeals agreed by a 9-6 vote, with all five Democratic nominees in the majority. In 2009, the court had 13 judges named by Republicans, four by Democrats.

Michigan's effort to eliminate straight-ticket voting, used more often by African-American voters than others, was blocked in federal district court by an Obama nominee and in the 6th Circuit Court of Appeals by an all-Democratic, three-judge panel.

District court judges named by Obama and Clinton in Wisconsin ruled against separate elements of that state's voting restrictions. One of the rulings was overturned by an all-Republican panel of the 7th Circuit Court of Appeals.

In Ohio, a district court judge named by George W. Bush agreed with voting rights advocates that the state's elimination of "Golden Week" — when voters were able to register and vote together — was discriminatory. But a 6th Circuit panel voted 2-1 along party lines to restore the restriction, and the Supreme Court on Tuesday refused to block it from taking effect.

In Virginia, where a Republican-nominated district court judge upheld the state's photo ID law, a panel of the 4th Circuit appeals court is scheduled to hear the case next week.

As was the case in Texas, voting restrictions in Kansas and North Dakota have been turned aside with the help of Republican-appointed judges. Both those states nevertheless are considered solidly Republican in November.

In Arizona, Democrats are challenging the state's rules for collecting absentee ballots and counting votes cast in the wrong precinct. A settlement was reached with Maricopa County regarding the number of polling places needed in November to reduce the risk of long lines that marred the state's March primary.

And in Georgia, a coalition of civil rights groups went to court Wednesday challenging the state's voter registration rules.

The Supreme Court has itself to thank for many of the state legal skirmishes. In 2013, it struck down a key part of the Voting Rights Act that had required states with a history of discrimination to get federal permission before changing voting procedures.

The court's rulings on a state-by-state basis merely settle what rules will be in place for the upcoming election; the full cases continue to be fought out. This year, the justices have ruled against restrictions in North Carolina and Michigan while upholding Ohio's. In 2014, they let restrictions stand in North Carolina, Ohio and Texas, while blocking them in Wisconsin.