In late June, a Los Angeles Times/Bloomberg News poll pegged the president's approval rating at 42 percent, while a Fox News survey put it at 41 percent. Then a July 6-9 Gallup Poll of 1,007 adults found an approval rating of 40 percent.
Looking at Bush's Gallup ratings so far this year, four distinct periods emerge. His job-approval rating averaged 41.3 percent in the Gallup Polls conducted during the first two months of 2006. The average fell to 36 percent in the five March and April surveys.
In Gallup's two May polls, Bush's numbers hit rock-bottom, averaging 32 percent. In the four conducted in June and early July, his average was back up to 37.8 percent -- most of the way back to where it stood in January and February.
But where has Bush gained ground? His standing among self-identified Democrats hasn't changed much. In January and February, they gave him approval ratings averaging just 9.8 percent. In March and April, that average ticked up to 10.2 percent, then dropped to 8 percent in May before edging back up to 9.3 percent for June and July.
That isn't a lot of fluctuation. So, Democrats aren't the ones who have boosted Bush's popularity in recent weeks.
Among independents, Bush's approval rating was 31.5 percent in January and February, then dropped to 25 percent in March and April, and fell another half point in May before rising to 30.8 percent in June and July -- almost back to what it was in the first two months of the year.
The biggest swings have occurred among Republicans. In January and February, Bush's approval averaged 83.3 percent among members of his party, then dropped 6.1 points in March and April polling, to 77.2 percent. In May, his GOP approval dropped again -- to 69 percent -- then popped back up by 9.5 percentage points in June and early July, to 78.5 percent.
The variance between the president's high at the beginning of the year and his valley in May is a whopping 14.3 percent -- far greater than his 6.5-point variance among independents and 2.2-point shift among Democrats.
While, clearly, the greatest fluctuation in Bush's support was among his fellow Republicans and his recovery is due to their returning to the fold, he is still 4.8 points lower among Republicans (in the June and July polling) than he was in January and February.
On the one hand, these numbers suggest that Bush can pick up another point or two just by regaining Republicans who have defected since the first of the year. For the president, that's the good news. The bad news for him is that the fluctuation among Democrats and independents has been so slight that he is unlikely to ever regain his popularity with either group.
Although these facts would seem to justify the focus-on-the-base strategy that many Republicans have been advocating in recent months, GOP pollsters privately say that the ground Bush needs to recover is among moderate, not conservative, Republicans.
They say that the conservatives, whose focus tends to be on social and cultural issues, are back, and that moderate Republicans, who are more interested in economic issues than cultural ones, are the voters whom Bush needs to court. Continuing to emphasize cultural issues might even be counterproductive, the pollsters warn.
With less than four months until Election Day, the Republicans' challenge is to energize their conservative base without antagonizing their moderates, especially the suburban soccer moms and professional women who have strayed from the GOP column in increasing numbers in recent years.
That's the needle that the Republican Party must thread if it is going to hold its very precarious House majority and ensure its continued control of the Senate.