Most striking is McCain's progress, immediately after the GOP convention, in underlying assessments of his candidacy.
It's not only about Palin; McCain also has gained ground in his effort to wrest the mantra of change away from Obama, crucial in an election with such a high level of economic discontent.
While McCain trails Obama by 12 points among registered voters in trust to "bring needed change to Washington," that's down from a 32-point Obama lead on this attribute in June. And while half continue to think McCain would lead the country in the direction of the unpopular George W. Bush, that's down from 57 percent before the conventions.
Moreover, 46 percent of McCain's supporters now are "very" enthusiastic about his candidacy, a striking improvement from 28 percent late last month, with women showing the most movement.
Among white women who support McCain, 51 percent now say they're very enthusiastic about his campaign, up from 30 percent in late August. High-level enthusiasm rose by a more sedate 10 points among men, to 39 percent.
Views of Palin are highly partisan, as noted in an ABC News poll last Thursday, and registered voters in this survey divide evenly, 47-45 percent, on whether or not she has the kind of experience it takes to serve effectively as president. Nonetheless she does inspire personal affinity in her peer groups.
Her high 67 percent favorable rating among white women goes higher still, to 80 percent, among white women with children at home. And 71 percent of white mothers say the pick makes them more confident in McCain's decision-making as president.
Even with her benefits, there's some division in the Palin pick. Among all registered voters, 49 percent say it makes them more confident in McCain, but 39 percent say it makes them less so.
Obama's pick of Biden carries less controversy: Fifty-four percent say it makes them more confident in Obama, just 29 percent less so.
There's another matter on which McCain still has some trouble: Forty-two percent of registered voters say they're uncomfortable with the idea of his taking office at age 72 -- not a majority, but a substantial number, and little changed from 45 percent last month.
Obama's chief challenges in his own convention were to respond on readiness, define change and win over former Clinton supporters. He hasn't advanced on them.
Fifty-three percent of registered voters say he has not done enough to define what he means by change; it was a similar 50 percent in July. And they divide exactly evenly, 48-48 percent, on whether Obama has the experience it takes to serve effectively as president; it was a similar 50-47 percent last month.
Then there are former Clinton supporters.
In this poll 72 percent of them are behind Obama for the nomination, 23 percent for McCain -- much like the 70-20 percent division before the Democratic convention, at which Clinton expressed full support for her former rival. Just 50 percent of Clinton supporters say they're "definitely" for Obama.
At the same time, as noted, 64 percent of Obama's supporters are highly enthusiastic about his candidacy, still substantially better than the level of enthusiasm for McCain and up from 52 percent before the conventions. That indicates the continued potency of Obama's campaign; enthusiasm can be critical in getting out the vote.