WASHINGTON (AFP) - Republican vice presidential pick Sarah Palin has given party nominee John McCain a jolt in several critical election battlegrounds, notably among white women voters, new polls found Thursday. But while McCain has extended his lead in the Quinnipiac University survey in Florida and cut Barack Obama's lead in Pennsylvania, the Democrat widened his advantage in Ohio, the decisive state in the 2004 election. Ohio, Pennsylvania and Florida have been fiercely fought over in recent elections and are among the clutch of battlegrounds where Democrats and Republicans each consider they have a chance of victory on Nov 4. The Quinnipiac survey had McCain leading in Florida, site of the infamous recount saga in the 2000 election, by 50 to 43pc compared to a 47 to 43pc lead on Aug 26 before the two party nominating conventions. In Pennsylvania, Obama, who is hoping to become America's first African American president, led by 48 to 45pc but his lead over McCain was halved from the 49 to 42pc margin in the previous Quinnipiac poll. But in Ohio, often seen as a microcosm of the US political map, with its urban Democratic voters and rural conservatives who can swing either way, Obama was up 49 to 44pc compared to a 44 to 43pc lead in the last poll. "White women, a key demographic group in any national election, appear to be in play with some movement toward Senator McCain in Pennsylvania and Ohio," said Peter.  Brown, assistant director of the Quinnipiac University polling institute. "Obviously, Governor Sarah Palin is having the impact that Senator McCain hoped when he selected her." "The size of Senator McCain's margin with white voters overall tells the tale. "In Florida, where McCain leads among whites by 24 points, that is a large enough cushion for him to survive Obama's almost total control over the black vote, and strong support among Hispanics. "But in Pennsylvania and Ohio, where McCain leads by just six or seven points among whites, he's behind in the total count."