Polls, Lies, and Damn Lies #1

An IPSOS poll, taken at the beginning of August, about which a great hullaballoo has been made in the media because it gives President Bush a failing grade, has a fatal flaw. That flaw is in the make-up of the pollees. It does not reflect the percentage of Republicans and Democrats presently making up the electorate.
As you can see from this PDF file, the Democrats make up 49% of the respondents, while Republicans make up only 39%. Hardly representative of US voters judging by the last Presidential election. The excerpt below shows the details of the flaw.

Do you consider yourself a Democrat, a Republican, an Independent or none of these?* (IF “DEMOCRAT” TO Q.2a, Q.2b ASKED. IF “REPUBLICAN” TO Q.2a, Q.2c ASKED. IF “INDEPENDENT” or “NONE OF THESE” TO Q.2a, Q.2d ASKED. RESULTS SHOWN IN SUMMARY BELOW.) 2b. Do you lean strongly or only moderately toward the Democratic Party? 2c. Do you lean strongly or only moderately toward the Republican Party? 2d. Do your beliefs tend to lean more toward the Democrats or the Republicans? REGISTERED VOTERS Strongly Republican .......................... 19% Moderately Republican ...................... 20% Definitely Independent/neither.............. 11% Moderately Democrat......................... 27% Strongly Democrat ............................ 21% Refused/not sure................................. 2% Total Republican ............................... 39% Total Democrat ................................. 49% * Half the respondents were asked party identification in this location, the other half were asked at the end of the survey with the other demographic questions. Results for the respondents who were asked the question early were 41% Republican, 47% Democrat. For the respondents asked later in the survey, the results were 37% Republican, 50% Democrat.