It's not Obamacare that is Democrats' big problem in the 2014 midterms. It's the intensity surrounding Obamacare that should be very worrisome to the party's candidates.

To start, consider the most recent Washington Post-ABC News poll that showed that the public was split down the middle over the law. Strong opposition to the law outpaced strong support overall in the survey. And strong Republican opposition surpassed strong Democratic support. The following chart tells the story.

new poll out Thursday confirmed what other recent surveys have also shown: Democrats' overarching health-care message is doing better than the alternatives in the eyes of the public, but intensity is a worry for the party. In the NPR survey conducted by Democrat Stan Greenberg and Republican Whit Ayres, 49 percent say "keep-it-but-fix-it" comes closer to their opinion on the Affordable Care Act as compared to 44 percent who align themselves with the predominant GOP posture, which is that the law has done more harm than good.

Both Republican and Democratic voters are lined up behind their party's message. In fact, Democratic intensity in support of "keep-it-but-fix it" is a bit higher than GOP intensity for its party's line. But independents line up with the Republican approach. Forty-two percent side strongly with the Republican message while just 33 percent side strongly with the Democratic one. Overall, independents align themselves with the GOP posture 50 percent to 43 percent.

Other polling has also shown that intensity isn't on Democrats' side in the lead up to the elections.

In a recent Wall Street Journal/NBC News survey, 47 percent of voters said they would be more likely to vote for a candidate who supports repealing the law compared to 32 percent who said they would be less likely to do so. When it comes to candidates who support keeping and fixing the health-care law, voters were split; 45 percent said they would be more likely to vote for such a candidate and 42 percent said they would be less likely to do so.

All of these findings are problematic for Democrats looking to boost turnout among their base as Republicans are spending millions trying to make the 2014 campaign all about Obamacare.

There's already electoral evidence to suggest that Republicans have the high ground on health-care intensity: The results of the recent Florida special election. In a swing House district, the Republican candidate who supported repealing the law defeated the Democrat who supported keep-it-but-fix-it. Obamacare was a central issue in the campaign.

Democrats do not appear to be overhauling their stance on Obamacare in the wake of the disappointing loss. Three Democratic senators facing reelection this year recently offered up a set of specific proposals to fix the law. Democrats have been doing this kind of thing for months. They are also doubling down on their effort to hit Republicans for wanting to repeal the law. "We're going to hold them responsible with a robust offense on what repeal means," Democratic Congressional Campaign Committee Chairman Steve Israel (N.Y.) old reporters Wednesday.

But it has been easier for Republicans to campaign against the law than it has been for Democrats to campaign for it. This is a reality of politics: Opposition is a very powerful way to rally the base and get them to vote.

Midterm elections are about base intensity. So, when it comes to Obamacare, Democrats can win the battle (being on the side of public opinion) and lose the war (the midterms).