Obama's second-term slump

President Barack Obama pauses while speaking in the East Room of the White House in Washington, Monday, June 10, 2013, during a ceremony to commemorate the 50th anniversary of the Equal Pay Act.
AP Photo/Evan Vucci

This post originally appeared on Slate.

Barack Obama's poll numbers are sliding.

Around Christmastime, his average approval rating, according to RealClearPolitics, was nearly 54 percent, 12 points higher than his average disapproval rating of 42 percent. Now his numbers have flipped. His average approval rating at 46.6 percent is roughly 2 points lower than his disapproval rating at 48.3 percent. If these numbers hold, President Obama is never going to get re-elected.

Obviously, Obama is not up for re-election, which raises the question: How important are approval ratings for his second term?

House Republicans aren't suddenly going to stop listening to him if his numbers decline. They're already ignoring him and not embracing his agenda.

In the elections of 2014, vulnerable Senate Democrats are competing in states where the president's approval rating has stunk for a long time. It won't be affected by a national drop; it can't go much lower.

In this constricted climate, Obama's falling approval ratings may be less important than for past presidents, except in one key area: implementing health care reform. It is the president's signature legislative achievement, but he needs to convince the public to sign up. To do that, he still needs them to trust him.

The traditional view of the approval rating is that it gives us a fix on the status of the president's power to persuade other lawmakers on a given day. If the president's approval rating is high, politicians will be more easily convinced. They won't want to upset voters who are apt to listen to the president or who are rooting for him. Or, as in high school, they'll simply want to associate themselves with the ideas of the popular guy. Approval rating is the power setting on the bully pulpit.

Presidential historians have long debated how much a president can persuade the public, even when his approval numbers are high. (These powers are more limited than popular perception holds.) Still, a president's public voice and ability to set the agenda are the best tools he has to shape domestic matters and help him sustain support for the foreign engagements he has the power to launch. But what if the politicians he needs to convince live in a separate political universe de-linked from the president? If so, his approval rating won't matter.

House Republican conservatives will determine whether immigration reform passes or whether a meaningful budget deal can be reached. Many of those House Republicans couldn't care less about the president's approval ratings: Their constituents dislike the president and are probably never going to change their mind. (That might change if Obama's approval rating was 65 percent, but that's not possible until the economy is booming.)

For this reason, on many issues, even if the president's approval rating were 5 points higher, it wouldn't matter. Partisanship has made any presidential connection toxic. When the president associates himself with an issue, it is more likely to turn Republicans against it and therefore decrease its chances of passing.

We're seeing this with immigration reform, where Obama has purposefully stayed in the background during Congressional negotiations at the advice of Republicans who say if he campaigns for the measure, he will make it harder for them to pass the bill. (Immigration reform will pass only if Republicans believe that it is in their self-interest, which has little to do with Obama's popularity.)