After a weekend at Camp David, President Obama is back at the White House today where he’ll begin his work week speaking on, what else, health care reform. Obama is scheduled to visit the Children’s National Medical Center here in Washington, where he’ll sit down with doctors before talking to reporters. In the words of Obama’s official WH schedule, he’ll use the moment to “press on health care reform.” Later today, he’ll no doubt bring up the topic again, when he sits down for interviews with NBC’s Today Show and PBS’s Jim Lehrer. As we blogged on Friday, it’s all an effort to seize the bully pulpit. Obama wants to use his personal popularity with the nation to get this health care bill through Congress.

But there are more signs today that Obama might not have the sway he needs on the issue. A new Washington Post/ABC News poll out today shows that while Obama’s overall approval rating remains high, the public isn’t so keen on his handling of health care. Back in April, around the time of his 100-day mark in office, Obama’s approval rating on health care was 57 percent. Now, as he marks his sixth month in office, Obama’s rating has fallen to 49 percent. Of those polled, 44 percent disapprove of how Obama has handled the issue. Back in April, that number was only 29 percent.

Perhaps most striking is where Obama seems to be losing most of his support: independent voters. According to the Post, 49 percent of independents polled disapprove of Obama’s handling of health care, while only 44 percent approve. Compare that to April, when the numbers were nearly reversed. Back then, 53 percent of independents thought Obama was on the right track, while only 30 percent disapproved. Why is this important? Obama won the White House with the support of independent swing voters. If he loses them, he’s losing his political base.

What does this all mean? We’re likely going to hear a lot more from Professor Obama this week. The last time we saw him was during the fight over the stimulus bill, when the president used his bully pulpit to explain exactly how the nation had gotten to this point and why a bill was needed to fix it. It was how we imagine Obama taught his classes on constitutional law at the University of Chicago: calm, logical and thorough. But will the same tactic work on health care, an arguably far more contentious issue? The next two weeks look to the biggest test of Obama’s young presidency so far.