Determined to stop gay marriages, Republican senators said Wednesday they will move later this month to consider several versions of a constitutional amendment (search) to block the same-sex unions.

But opponents on both sides of the political aisle said supporters fall far short of the votes needed in the House and Senate to amend the constitution. And any attempt to do so, said Sen. Russ Feingold, D-Wis., is a "divisive political exercise" aimed at influencing this year's election.

Sen. John Cornyn, R-Texas, said the recent scenes of gay couples marrying in San Francisco (search) and New York are starting to resonate with the public.

"The chances (of passing an amendment) are getting better the more the American people find out," said Cornyn, who held a hearing in a Judiciary subcommittee on the issue Wednesday. And, he added, "we should not waste time."

He said the Judiciary Committee could act on a bill "in the next few months."

Judiciary Committee Chairman Orrin Hatch, R-Utah, said he supports amending the constitution, but his proposal may be more limited and guarantee that states need not recognize gay marriages performed in other states.

So far, Sen. Wayne Allard, R-Colo., has introduced the only legislation on the issue, calling for a constitutional amendment defining marriage as the union of a man and woman. The bill has nine co-sponsors, including one Democrat, Sen. Zell Miller of Georgia.

But there is a broad and unlikely alliance — from liberal gay rights and civil rights supporters to conservative Republican federalists — forming in opposition to the amendment. They range from conservative Sen. Michael Crapo, R-Idaho, who doesn't believe an amendment is necessary, to the more moderate Sen. Lincoln Chafee, R-R.I., who said Congress shouldn't waste time on the matter when issues of war and the budget are paramount.

"Congress has better things to do than write bigotry and prejudice into the constitution," said Sen. Edward M. Kennedy, D-Mass., adding that the recent decision by the high court in his state to allow same-sex marriages does not bind other states.

But advocates are taking their cue from President Bush who last week called for swift action on an amendment banning gay marriage. Same-sex unions (search), said GOP Majority Leader Bill Frist, are likely to spread across American like a "wildfire." And amendment supporters said changing the constitution is the only way to stop activist judges from radically redefining marriage.