Rasmussen’s daily tracking poll shows little overall movement in the topline numbers today, with two-thirds of responses coming after Sarah Palin’s blockbuster speech at the Republican convention.  McCain trails now by one, and still by three when leaners are included.  However, Rasmussen detects a movement in a key demographic that could spell disaster for Barack Obama:

The Rasmussen Reports daily Presidential Tracking Poll for Saturday shows Barack Obama attracting 46% of the vote while McCain earns 45%. When “leaners” are included, it’s Obama 49%, McCain 46%. …

As McCain has begun to chip away as Obama’s convention bounce, most of his gains have come among women voters. Obama still leads 51% to 44% among women, but that seven-point edge is just half the fourteen point lead he enjoyed last Tuesday. McCain leads by three among men, little changed in recent days.

Seventy-seven percent (77%) of Obama voters now say they are voting with enthusiasm for their candidate while 17% are primarily voting against the other candidate. For McCain, those numbers are 65% and 28% respectively. Before the Republican convention, just 54% of McCain voters were voting enthusiastically for him rather than simply voting against Obama.

Two key shifts here are enthusiasm and women.  The Democratic convention did not produce a significant enthusiasm bounce for Obama, but one appears to have developed for McCain, who needs it more.  Women have apparently responded positively to the selection of Sarah Palin to the ticket, and McCain has halved the gender gap with a third of the respondents still having not heard her speech Wednesday.

The overall numbers for Obama’s bounce didn’t develop until Tuesday of this week, four days after the end of the convention.  Rasmussen warns against reading too much into the topline numbers until Tuesday or Wednesday.  The hesitancy in the numbers could also be the result of the deluge of smears and innuendo that hit Palin earlier in the week, and which only got debunked at the end of the convention or later.

McCain’s foundational numbers have begun to sharply improve since the Palin selection, and especially since her speech.  He appears ready to get a significant bounce coming out of the convention, but we’ll have to wait a little longer to see if it arrives.