By the way, when you look into it, you discover that the Politico poll of 1,991 people was conducted Online.

According to the Pew Research Center;
The accuracy of a poll depends on how it was conducted. Most of Pew Research’s polling is done by telephone. By contrast, most online polls that use participants who volunteer to take part do not have a proven record of accuracy. There are at least two reasons for this. One is that not everyone in the U.S. uses the internet, and those who do not are demographically different from the rest of the public. Another reason is that people who volunteer for polls may be different from other people in ways that could make the poll unrepresentative. At worst, online polls can be seriously biased if people who hold a particular point of view are more motivated to participate than those with a different point of view.

http://www.pewresearch.org/2010/12/29/how-accurate-are-online-polls/