Very interesting results from ABC News/Washington Post Poll Feb 18-22 via http://www.pollingreport.com.

"Would you support amending the U.S. Constitution to make it illegal for homosexual couples to get married anywhere in the U.S., or should each state make its own laws on homosexual marriage?" Options rotated

Amend Constitution State Laws No Opinion
ALL 46 45 9
Republicans 58 36 6
Democrats 44 48 8
Independents 35 56 9

unusually independents are to the left of democrats on this one.
Now the difference could be just plain sampling error. My back of the envelope calculation says the standard error due to sampling alone of the difference dem-independent is about 4%, that is about equal to half the difference (actually to be honest top of my head I didn't even use an envelope).

However, if this is true (and it could be given age distributions of independents and attitudes) Bush's endorsement of an amendment would be a political mistake. The election is decided by independents and if they are against the amendment his unscrupulous strategy is also dumb.

Also, I guess, support for an amendment will decline when people begin discussing the text as in "legal incidents thereof" and realise that amending the constitution is very dangerous.

(tech note standard error due to sampling assuming all really about 50 50 yes so the variance of answer yes for each respondent is 0.25 (really less as some say don't know), Dem Rep indep about 1/3 1/3 1/3 so dem and indep samples probably around 300 to 350 (guess 300) so var number dems says yes is about 75. The var of fraction of dems say yes around 1/1200. Var of dif dem-indep = sum of variances = 1/600. Standard error of dif a little over 1/25 = 4%. )