AFTER A MONTH…. Gallup released its latest survey this morning, showing President Obama’s approval rating at 63%, “down slightly from his initial 68% rating in January.”

I should note from the outset that a modest drop in a president’s first month isn’t worth getting too excited about. A 63% approval rating is still, obviously, quite strong, and higher than most modern presidents at this point in their first terms.

What’s interesting, though, is why Obama dropped a bit.

If Gallup’s numbers are right, Obama has seen his support go up over his first month with Democrats and Independents, but his overall number fell because he’s lost Republican support. The report noted, “More precisely, the steepest drop in approval of Obama has come from conservative Republicans, whose support descended from 36% in his first, partial week on the job (Jan. 21-25) to 22% by his fourth week (Feb. 9-15).”

This is to be expected. Obama enjoyed some GOP support early on, but it dissipated once the president started governing and Republican lawmakers (and their allies) started criticizing. Since the president’s numbers actually improved among everyone else, it shouldn’t trouble the White House too much to lose support from, as Eric Kleefeld noted, “people who were unlikely to have approved of him in the first place.”

I’m skeptical that the president’s overall numbers have too big an impact right now. A month is, after all, only a month. But if Republicans were watching these numbers, hoping to see a decline they could exploit in the wake of the stimulus debate, they’re probably disappointed right now.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.