In a landslide vote Tuesday, Ohio voters approved a measure to combat gerrymandering of the state's legislative districts, 71 percent to 29 percent.

The measure ensures that each major party will have at least two seats on the state's redistricting commission. It also says that new maps will be thrown out after four years rather than 10 if they don't get bipartisan support, and adds a line to the state constitution saying that no legislative districts "shall be drawn primarily to favor or disfavor a party."

Now, the changes do not apply to the state's seriously gerrymandered congressional districts. These are still drawn by the legislature and are subject to approval from the governor. However, reformers' victory here will surely inspire them to push for similar changes on the congressional level — and likely on the 2016 ballot.

The state's congressional districts are really gerrymandered — and this measure doesn't change that

Since this decade's redistricting, Ohio — which President Obama won twice — has had one of the most Republican-gerrymandered congressional delegations in the country. In 2012, Republican candidates won just 52 percent of the statewide House vote — and 75 percent of the House seats (12 out of 16 seats). Here's what the map looked like:

All four Democrats won with 68 percent or more of the votes in their districts — and every Republican with a declared opponent won by relatively smaller margins, between 53 and 63 percent.

This is a classic sign of gerrymandering — the Democratic vote was packed together in a few districts, and the Republican vote was spread out over many, while still having a clear advantage in most of them. Another classic indicator? In 2014, despite massive Republican victories in the state and nationwide, not a single House seat changed partisan hands. The year of Obama's reelection and the year of the GOP landslide had the same outcome for the Ohio congressional delegation.

The measure approved on Tuesday does nothing about this, at least directly. Ohio's congressional districts are drawn by the legislature, and subject to the governor's approval — not by an outside commission.

But already, reformers hoped to put a similar measure applying to congressional districts on the 2016 ballot, as Jim Siegel of the Columbus Dispatch reported in October. And they had supporters from both parties. "It's truly not about what's good for one party. It's about what's good for the system," Republican state Sen. Frank LaRose testified then. Tuesday's victory will surely give this effort even more steam.

What the ballot measure changes for Ohio's legislative redistricting

Previously, Ohio's legislative districts were redrawn by a commission with five members — the governor, state auditor, secretary of state, and one member of the legislature from each party.

That meant that if one party won statewide before redistricting, it would control four of those five seats — and be able to steamroller the one minority party member. And that's what happened after the Republican wave in the 2010 elections.

The newly approved reform measure makes partisan redistricting more difficult in a few ways:

It expands the redistricting commission to seven members, and now features at least two guaranteed members of each of the two major parties in the legislature. So already, both parties have more of a voice.

If the commission's members approve a district plan that doesn't have the support of at least two members from each party, the plan will only last four years. Conversely, if a plan does get bipartisan support (at least two supporters from each party), it will last the full 10 years. This incentivizes a bipartisan plan.

The Ohio constitution will now state that no legislative districts "shall be drawn primarily to favor or disfavor a party." This could have significant implications to court challenges of any plans viewed as too partisan, as seen in Florida. Districts are also required to be contiguous and compact.

So if reforms like these are adopted for the Ohio's congressional districts in 2016, it could have a major impact on one of the most gerrymanderedHouse delegations of them all.