NBC and Marist polls in three key states won by Barack Obama in 2008 show that the incumbent is far from making the sale in 2012.  Mitt Romney has gained significant ground in all three states, seen as must-wins by both campaigns, but still trails for the moment in Florida, Virginia, and Ohio:

President Barack Obama holds a narrow advantage over presumptive Republican nominee Mitt Romney in three of the most pivotal presidential battleground states — Florida, Ohio and Virginia — according to new NBC-Marist polls.

But in each of these states, Obama’s share of the vote is below the 50 percent threshold usually considered safe haven for an incumbent president, and Romney has narrowed the margin in these three battlegrounds since earlier this year.

In Florida and Virginia, Obama leads Romney by an identical four-point margin, 48 percent to 44 percent, among registered voters, including those who are undecided but leaning toward a particular candidate.

In Ohio, the president is ahead by six points, 48 percent to 42 percent.

In March NBC-Marist polls — conducted during the middle of the GOP primary season — Obama led Romney by 12 points in Ohio (50 percent to 38 percent), and by a whopping 17 points in Virginia (52 percent to 35 percent). In January, Obama was ahead of Romney by eight points (49 percent to 41 percent).

The trends look poor for the President, but what about the reliability of the numbers themselves?  Let’s take a quick look at the D/R/I splits in all three polls and compare them to 2010 and 2008:

• Florida: Marist 43/35/21, 2008 37/34/29, 2010 36/36/29
• Virginia: Marist 31/29/39, 2008 39/33/27, 2010 N/A (No Senate or gubernatorial election)
• Ohio: Marist 37/28/34, 2008 39/31/30, 2010 36/37/28

In other words, Marist uses a model in Florida that assumes Democratic turnout will be six points higher than in 2008 and seven points higher than in 2010, while Republican turnout remains largely the same, which means that independents vanish.  In Ohio, Marist assumes Democratic turnout will be only slightly lower than 2008, while Republican turnout craters below their nadir in 2008 and ignores the big GOP turnout in 2010.  Only Virginia looks like a somewhat rational predictive model for the 2012 election, although they significantly oversample independents.

Don’t forget that we’re also looking at registered voters in these models, too, not likely voters.  By this time, pollsters should be able to start applying likely-voter models, and in fact the Marist poll’s tables do have some data on which to build those models.  That data doesn’t look good for Obama, though.  Asked to rate their interest in the presidential election from 1 to 5 with 1 being the most interested, 72% of Virginia Republicans gave a 1, while only 60% of Democrats and 56% of independents did the same.  Combining 1 & 2, the D/R/I for enthusiasm in Virginia is 72/78/67.  For Florida, 1-only D/R/I is 68/73/52, 1&2 D/R/I 77/81/66.  In Ohio, respectively, it’s almost even at 63/63/54 and 75/74/64.

The actual status for Obama in these three swing states is more dire than the toplines of these three surveys show, and it’s trending downward for Team O.