If those were the only numbers we had, it would give the illusion that the Republicans are actually increasing in popularity -- but that is not the case. Actually, the Republicans are losing popularity with the public. The reason is because most of the 40% who say they are Independents really lean toward (and usually vote for) either the Democrats or the Republicans. Only about a quarter of those saying they are Independents don't lean toward either party -- about 10% of the population in 2011 and 11% in 2012. And the truth is that the other three-quarters of these "leaning" Independents are trending away from the Republican Party.
In 2011, about 18% of those "leaners" preferred the Republican Party (giving Republicans about 45% of the population), while only 14% preferred the Democratic Party (giving them about 44% of the population). That meant the two parties were virtually tied, since those numbers are within the 1 point margin of error. But since the Republicans threatened to shut the government down in 2011, and are still displaying their preference for the policies of the extreme right, Independents have been moving away from the GOP and toward the Democrats.
The 2012 numbers reflect this. Now 16% of Independents are Democratic "leaners", and only 14% are Republican "leaners". This means the Democrats are now preferred by 47% of the population, while Republicans are preferred by only 42% of the population.
If the Republicans continue with their ridiculous plan to force benefit cuts to Social Security and Medicare by refusing to raise the debt ceiling and shutting down the government by forcing it into default, they will lose even more of those Independents. I hope the Democrats don't give in to the Republican threats, because it looks to me like the Republicans are doing a pretty good job of committing political suicide. They aren't even backed in this fight by their biggest contributors -- Wall Street and the business community.