President Obama now trails Mitt Romney by four points among likely voters in the first major survey conducted since last week’s presidential debate.

The Pew Research Center poll released on Monday showed Romney ahead 49 to 45 among likely voters, a huge turnaround from Pew’s September survey, which showed the president ahead 51 to 43.  This finding is significant: Pew is a well-respected polling organization and this is one of the first surveys released in which all of the participants were interviewed after the debate, which even Democrats say Romney performed better than the president in.

In the poll, Romney made huge gains among women. Obama lead among female voters 56 percent to 38 in September, but now the two are tied at 47 percent each. White voters now favor him by 21 points, up from seven last month.

Forty-seven percent of voters described Romney as the candidate with “new ideas,” compared to 40 percent saying that of the president. Obama’s lead in terms of which candidate is viewed as “strong leader” has also disappeared.

To be sure, other polls still show the president ahead. And it will be important to watch polls in individual states, as that ultimately decides who wins the race.

Follow Perry Bacon Jr. on Twitter at @perrybaconjr