Gone is Barack Obama's significant lead: Now 46 percent of registered voters say they lean towards the Democratic nominee, versus 43 percent towards McCain -- well within the margin of error.
Pew's June survey gave Barack Obama a lead of 48 percent over McCain's 40 percent. In July, his lead shrank to five percentage points, 47 percent to 42 percent.
The Pew Center's report attributes the change to a higher level of support for McCain among evangelicals, Republicans and white middle-class voters. His image as a leader also improved.
Obama has made little gain among his base supporters; 83 percent of Democrats support him while 87 percent of Republicans back McCain. Among Sen. Hillary Rodham Clinton's (D-N.Y.) former supporters, 72 percent support Obama. Among former backers of previous Republican presidential candidates, 88 percent back McCain.
However, Obama supporters tend to be more enthusiastic about their candidate; 58 percent of Obama's backers call themselves "strong supporters" while only 39 percent of McCain's said that.
One third of the voters were considered swing voters. Among them, 12 percent are leaning toward Obama, 11 percent are leaning toward McCain and 10 percent are undecided.