The Supreme Court's split decision on gay marriage leaves the issue of legalization up to states. As we've noted, a number of states have existing bans on the practice. But which states might be in line to completely legalize marriages between same-sex couples?

It perhaps goes without saying that attitudes toward gay marriage are all over the place — some states strongly oppose the idea, many embrace it. Polling on the subject is equally disparate. Some small states haven't had statewide polls on the topic. Others have polls that date back a year or two, during which a lot has changed nationally. The Times' Nate Silver tried to parse how attitudes might have shifted over time in a post in March, but even his data was largely predicated on 2008 polling.

We looked at the most recent public polling for each state to try and assess where action might be expected. In only five cases — Wyoming, Oklahoma, Idaho, and the Dakotas — did we need to rely on aggregated regional polling; in every other case, we were able to find at least one poll on the topic. Full poll results (with links) are at the bottom of this post; we took that data and created a few maps.

Most recent polling

The first map shows the most recent polling for each state. The darker the color, the broader the support. (Mouse over for percentages.)
But that map is a little deceptive. After all, some of the states already allow same-sex marriage. In this map, we've colored those states blue. Every other state shows a different level of red coloration; ones with more support for gay marriage are more red.

It's interesting to note that the states that have not yet legalized gay marriage but show the highest levels of support are generally those adjacent to states that have passed such laws. The region with the lowest level of support for the legislation is the South, with the exception of Florida.

Ranking of support among states still to legalize

If we assume, then, that the rest of the states will follow the same path as their peers and approve gay marriage, when might we expect it will happen? We took the remaining states and ranked them, 1 to 37, in order of strength of support for gay marriage. The darker the state on the map below, the more likely it is to pass gay marriage, based solely on level of support.

You'll notice two things. The first is that New Jersey, Michigan, and Virginia all stand out — but so do states in the Southwest and Oregon. The second is that this ranks every state, even those that strongly oppose gay marriage. Like, say, Mississippi, which Silver pegged as the state most likely to approve gay marriage, and which came in dead last in our survey, too.

If we limit the map to only those states with 50 percent or more support, it looks like this.

The cut-off comes at Illinois, which hovers around the 50 percent approval mark. As if to prove the point, Illinois is also one of the most recent states to attempt to pass same-sex marriage legislation. At the end of last month, that effort collapsed.

Update: An earlier version of this article mistakenly attributed a national poll to the state of Oklahoma.

States still to legalize

  • New Jersey, 64% support - 30 % opposition (3/2013)
  • Michigan, 57% support - 38 % opposition (5/2013)
  • Virginia, 56% support - 33 % opposition (5/2013)
  • Arizona, 55% support - 35 % opposition (5/2013)
  • Hawaii, 55% support - 36 % opposition (1/2013)
  • Nevada, 54% support - 43 % opposition (2/2013)
  • Oregon, 54% support - 40 % opposition (12/2012)
  • Pennsylvania, 54% support - 41 % opposition (5/2013)
  • Colorado, 51% support - 43 % opposition (4/2013)
  • Illinois, 50% support - 29 % opposition (2/2013)
  • Tennessee, 49% support - 46 % opposition (5/2013)
  • Ohio, 48% support - 44 % opposition (4/2013)
  • Texas, 48% support - 48 % opposition (1/2013)
  • Indiana, 45% support - 45 % opposition (12/2012)
  • New Mexico, 44% support - 51 % opposition (5/2013)
  • North Dakota, 44% support - 46 % opposition (aggregated by region, 11/2012)
  • South Dakota, 44% support - 46 % opposition (aggregated by region, 11/2012)
  • Wisconsin, 44% support - 46 % opposition (2/2013)
  • Florida, 43% support - 45 % opposition (12/2012)
  • Montana, 43% support - 49 % opposition (2/2013)
  • North Carolina, 43% support - 46 % opposition (4/2013)
  • Alaska, 40% support - 57 % opposition (2/2013)
  • Idaho, 40% support - 51 % opposition (aggregated by region, 11/2012)
  • Wyoming, 40% support - 51 % opposition (aggregated by region, 11/2012)
  • Missouri, 36% support - 52 % opposition (6/2012)
  • Oklahoma, 35% support - 56 % opposition (aggregated by region, 11/2012)
  • Kansas, 34% support - 63 % opposition (2/2013)
  • Alabama, 32% support (4/2013)
  • Nebraska, 32% support (10/2012)
  • Louisiana, 29% support - 59 % opposition (2/2013)
  • Utah, 29% support - 71 % opposition (7/2012)
  • Georgia, 27% support - 65 % opposition (12/2012)
  • Kentucky, 27% support - 65 % opposition (4/2013)
  • West Virginia, 26% support - 61 % opposition (9/2011)
  • South Carolina, 21% support - 69 % opposition (9/2011)
  • Arkansas, 18% support - 75 % opposition (10/2012)
  • Mississippi, 13% support - 78 % opposition (11/2011)

States where it's already legal (or will be soon)

  • New York, 60% support - 33 % opposition (12/2012)
  • Rhode Island, 60% support - 26 % opposition (2/2013)
  • California, 58% support - 36 % opposition (6/2013)
  • Massachusetts, 58% support - 32 % opposition (5/2013)
  • Vermont, 58% support - 33 % opposition (8/2011)
  • Maryland, 57% support - 37 % opposition (11/2012)
  • New Hampshire, 56% support - 34 % opposition (4/2013)
  • Delaware, 54% support - 37 % opposition (3/2013)
  • Maine, 53% support - 43 % opposition (1/2013)
  • Washington, 52% support - 42 % opposition (11/2012)
  • Connecticut, 51% support - 48 % opposition (8/2012)
  • Iowa, 49% support - 42 % opposition (10/2012)
  • Minnesota, 49% support - 45 % opposition (5/2013)