So the U.S. Supreme Court has refused the Ohio GOP’s request to overturn an appeals court decision to reinstate early voting on the weekend and Monday before the election. This is a big, big victory for the Obama campaign, and it could arguably make a difference to the outcome in the critical state of Ohio.

Remember, this is something the Romney campaign opposed. As you may recall, the Obama campaign this summer sued to restore in-person early voting for all Ohio voters, and not just members of the military. The Romney campaign falsely claimed this was an effort to “undermine” military voting rights, when in fact it was an effort to expand voting rights, not limit them.

It isn’t hard to see why the Romney camp opposed an expansion of voting rights. More early voting makes it easier for more people to vote — particularly minorities and lower income voters — which will likely help Obama.

Right now, it’s not clear how much of a lead Obama holds in Ohio. It’s possible that it is slimmer than state polls suggest, if in fact things are narrowing there along with the national tightening of the race. But the fact that Ohio may very well end up being an extremely tight finish is what makes this decision a big deal for the Obama camp, in a state that may be pivotal to the whole election’s outcome.

Dems have argued that as many as 100,000 people voted during the three days prior to the election in 2008. What’s more, Dems hope they have built a superior early voting operation. According to the Plain Dealer, Obama has 117 field offices across the state, versus only 40 for Romney. Republicans claim the GOP has done more door knocking, but Dems note that the claim is unsubstantiated.

Dems also hope that the decision will help them turn out African Americans to the polls. In particular, they note that early voting will now be possible on Sunday from 1 p.m. to 5 p.m., giving them a chance to urge African Americans to vote after church.

There are some signs early voting in Ohio is already favoring Dems. As my colleague Aaron Blake notes, Dems may be benefitting from larger early turnout in Franklin and Hamilton County — both Dem-dominated areas, thanks to urban centers like Columbus and Cincinnati. (There is also heavy early turnout in one GOP county).

If Romney is going to win this thing, this decision will probably mean he will have to mount a larger come from behind push in this state than he otherwise might have. That isn’t impossible, to be sure, but an Ohio win may have just gotten a bit tougher for him.

More broadly, this is only the latest sign that voting rights proponents have had more success this cycle than anyone expected in beating back efforts to limit voting, though it’s important to remember that the battle is far from won. As I noted here the other day, voting restrictions have proven to be the dog that didn’t bark in this election. Whoever wins the presidential race, this latest is another victory for democracy.


UPDATE: Ari Berman has more of the important backstory to this decision right here.