Legal battles across the nation over who is eligible to vote and whether and how their ballots will be counted are far from settled, even as early voting in some states is set to begin this month.

The latest battleground-state challenge comes Thursday in Pennsylvania, where the state’s Supreme Court is scheduled to hear arguments about whether a new law requiring voters to show specific forms of photo identification violates the state constitution’s guarantee of the fundamental right to vote.

A Commonwealth Court judge ruled the Republican-backed law was a reasonable demand to protect the integrity of the election process, rejecting arguments from Democrats and minority groups that it could disenfranchise hundreds of thousands of voters who lack the required ID.

That is only one in a series of court decisions and appeals that illustrate the murky nature of the nation’s voting debate.

The Pennsylvania decision aside, Democrats, minority groups and civil rights organizations have had a successful few weeks challenging an unprecedented number of voting-law changes enacted largely by Republican-led states where officials said they were trying to prevent voter fraud.

“There’s no question that we’ve won many more of the lawsuits than we’ve lost,” said Lawrence Norden, an official at the Brennan Center for Justice at New York University Law School, a leading opponent of the laws. He said seven laws in six states have been successfully challenged.

Florida on Wednesday agreed to terms with groups that alleged the state’s efforts to cull potential non-citizens from voting rolls targeted Hispanics. The state said it would have election officials contact 2,600 potential non-citizens on a list released this summer to tell them they were eligible to vote in the fall.

The state said Wednesday that after gaining access to a federal database of those registered as non-citizens, it found 207 names on voting rolls. The state originally had identified 180,000 possible noncitizens out of the state’s 11.2 million voters.

The state has not discovered whether any of the 207 had ever voted or were registered by accident, but Florida Secretary of State Ken Detzner said it showed the state has a “successful process to identify illegally registered voters.”

Those who opposed the state’s efforts said that they agreed non-citizens should not be on the rolls but that the state had spent much effort for little results and may have discouraged legitimate voters in the process.

“I still do not believe there is a big problem of non-citizens on the voting rolls,” said Penda Hair of Advancement Project, one of the groups that sued Florida.

Similarly, a search in Colorado turned up 141 potential non-citizens, but the state said it is too late to begin removing them from rolls if they are indeed non-citizens.

Much of the attention on the voting changes has centered on new voter-ID laws passed by many states, including several swing states.

Two state judges in Wisconsin have blocked implementation of that state’s law, saying it violates the state constitution’s protection of voting rights. Attorney General J.B. Van Hollen (R) has asked the state Supreme Court to overturn the decisions, but it is unclear whether the court will accept the challenge.

A panel of three federal judges in Washington has blocked Texas’s voter-ID law, saying it would impose “strict, unforgiving burdens” on poor and minority voters. Texas will appeal the decision to the Supreme Court, but said it is too late to try to implement the law in time for the November elections.

A similar panel of judges is considering a South Carolina voter-ID law.

There are two reasons for the seemingly contradictory judicial views on voter-ID laws.

The first is the burden of proof. Texas and South Carolina are among the jurisdictions covered by Section 5 of the Voting Rights Act, requiring them to prove to the Justice Department or federal judges that any new election standards would not harm minorities.

The evidence offered by Texas was “unpersuasive, invalid, or both,” according to U.S. Circuit Judge David S. Tatel.

In Pennsylvania, on the other hand, the burden was on challengers to prove that the law would prevent certain people from voting. Judge Robert Simpson said that the challengers still had time to obtain proper ID and that it is a “reasonable, non-discriminatory, non-severe burden when viewed in the broader context of the widespread use of photo ID in daily life.”

The second reason is that not all voter-ID laws are the same. The Justice Department, for instance, has approved laws in Virginia and New Hampshire that provide alternatives to a strict photo requirement but opposed the Texas and South Carolina laws.

Thomas Fitton, president of Judicial Watch, which supports the laws, said they reflect common sense and public acceptance.

“Despite all the noise, more than 30 states are going to have a voter ID requirement in the coming election,” he said.

Fitton said that will protect the electoral decision. Norden, of the Brennan Center, said it could lead to disenfranchisement.

Even if the recent challenges are upheld, Norden said, “in November 2012 it is going to be more difficult for many people to vote than it was in November 2010.”