A few years ago out in California a number of liberal interests PACs spent some serious movie star money running public opinion polls about the general public's views on giving driver's licenses to illegal aliens. Although the results of the poll reflected a slight 51-49 bias against it, the liberals were encouraged enough to put a proposition on the ballot to do just that. As soon as that proposition won qualification for the ballot, an opposing group drew up their own proposition against giving driver's licenses to illegals. When the election came around Californians overwhelmingly voted against illegal drivers licenses. Those liberal lobbyists up in Sacramento were stunned by the lopsided defeat and wondered how their polling failed them.
A few years later the libs were at it again. They ran a public poll to gauge support for legalizing gay marriage in California. As I recall the results were just about 55-45 in favor of gay marriage. However, again when election time came around the gay marriage proposition was defeated and an anti-gay marriage initiative won the day. Again a perplexed liberal contingent.
Then some doctoral students up at Stanford decided they would investigate this phenomena. After a couple of years of serious investigation they concluded that folks, when asked by another human being, what their opinion is on a particular issue, will often lie if they believe their opinion is not a "politically correct" one. And these same folks, while seemingly open to a popular liberal cause, will, in the privacy of the voting booth, vote their conscience and directly opposite what they avowed in the polling.
Of course, when the majority vote against gay marriage in California, it was neutered by the liberal courts, who essentially let Californians know who really runs their state...and it ain't the voters; the vote was for naught. And with issuing licenses to illegal Mexicans, after further illegal invasion, Sacramento liberals were emboldened enough to tell Californians to "shut up and take it" and recently rammed through a law allowing illegals to have a license.
Never the less, the essential truth is that opinion polls cannot always be a valid measure of popular support for an issue, that is until pollsters can some how remove a human voice from that rolling telephone poll (and mail surveys have proven to be too expensive and not timely enough(, you're going to have wide discrepancies in opinion polls. Folks will go to any lengths to hide their personal prejudices if they go against the "politically correct" response.
Still another problem with opinion polling has been the political candidate's involvement in polling. Go back thirty years or so and you will find that only two polling firms existed, both of which went to great lengths to stay nonpartisan. Today, thanks to the massive amounts of campaign dollars being funneled into campaign chests, politicians run their own polls. And, unfortunately, all too often, those polls will be structured to reflect numbers that are favorable to the candidate. A liberal candidate will fix their polling to insure more liberal demographics are used in polling and conservatives vice versa. So we, John Q. Public, have to take these polls with a grain of salt as they almost never reflect the true opinion of the electorate.
Even more manipulative and dishonest are the candidates themselves who are willing to spin even negative polls into something they "want" to believe, not what is actually out there. For example, the Obama/Reid/Pelosi regime continue to say a majority of Americans are in favor of the Senate's current version of immigration reform...that despite almost unanimous polling that shows 67% of us are against giving a pathway to citizenship for those who violated our immigration laws.
Finally the fallacy of public polling today is the "bringing up the rear" liberal support granted by the liberal main stream media. How else does one explain an MSNBC poll that purports to favor a liberal issue while independent polling shows directly the opposite opinion.
How many times have we heard a politician disregard a poll that shows them losing, while chattering like monkeys if one shows them to be leading. That should tell us all we need to know about the reliability of most opinion polls...the only opinion that really matters is yours...when you enter the voting booth.