President Obama makes a statement on the situation in Ukraine and Gaza, at the White House on Monday. (J. Scott Applewhite/AP)

Barack Obama has skated from crisis to crisis this summer, from insurgents invading Iraq, an avalanche of unaccompanied minors crossing the U.S.-Mexico border, the re-ignition of Israel-Palestinian violence and another contentious standoff with Russia.

But new polling finds that, despite a wave of bad news, Obama's job approval ratings have not budged. At all.

Here's what the data show:

  • A CNN/Opinion Research poll concluding Sunday found 42 percent approving of Obama, one point below June, May and March; 55 percent have disapproved in each of the last three polls.
  • Gallup's daily tracking poll released Wednesday found 42 percent approved and 51 percent disapproved -- similar to his 43-52 average since late May. Gallup's trend shows a dropoff of a few percentage points in June, but Obama's ratings actually recovering even as several domestic and international crises have gained steam.

Emory University political scientist Alan Abramowitz noted the consistent approval marks:

Obama's stable ratings, however, are not due to rave -- or even decent -- reviews for his performance on the big issues of the summer. Fully 58 percent disapproved of Obama's handling of young undocumented immigrants at the border in a Washington Post-ABC News poll last week, two weeks after 52 percent disapproved of his performance on Iraq, where much of the country has been overrun by Sunni insurgents. Asked about his foreign policy more generally, 55 percent disapproved in a Pew Research Center poll released last week, while just 36 percent approved.

At the same time, Obama's ratings don't appear to be buoyed by improving economic news, which has yet to change Americans' bleak outlook on the country's financial future. Only 19 percent of the public rated the economy as "excellent" or "good" in the Pew poll, even amid some of the best jobs numbers in years.

So what's maintaining Obama's ratings through repeated cycles of negative news? Partisan loyalty (and a loyal opposition) plays a big role. While Obama has drawn some friendly fire for his immigration efforts, this hasn't altered his lopsided 81 percent approval rating among fellow Democrats in weekly Gallup tracking data. And while Republicans are most critical of Obama's handling of Iraq and immigration, only about 10 percent approved of him before the crises flared up, leaving little room to drop.

And among independents, things haven't moved much for months either, regardless of world or U.S. events.

In other words, he might have hit his approval floor -- barring a major development that really shakes up the baked-in opinions of the president.

After six years in office, Obama has developed a bedrock of supporters -- around 40 percent -- that apparently won't write him off without a major catastrophe. George W. Bush's approval rating required several huge problems -- including the Iraq war, the bungled Hurricane Katrina response and (at the end of his term) the economic meltdown -- to sink well below 40 percent.

Some of Obama's most ardent critics might think he has failed in similar measure, but nothing has hit home as much as the three things listed above.

Still, the stability of Obama's job ratings cuts both ways, and his persistent negative marks continue to be a dead weight for Democrats in congressional contests in November. A slight majority of Americans continue to disapprove of the president, and a much larger share of the public "strongly disapproves" of Obama than strongly supports him, according to Post-ABC polling. It's even worse for Democrats in the Senate races that matter.

presidential approval polls

The presidents' party almost always loses seats in midterm elections, but unsurprisingly, unpopular presidents lose the most. Obama needs more than stable ratings to help fellow Democrats this fall. He needs them to get better.

Peyton M. Craighill contributed to this report.