Washington ? Some election-year advice to Republicans from a high-ranking source who has the president’s ear: Don’t use a proposed constitutional amendment against gay marriage as a campaign tool.

Just who is that political strategist? Laura Bush.

The first lady told “Fox News Sunday” that she thinks the American people want a debate on the issue. But, she said, “I don’t think it should be used as a campaign tool, obviously.”

“It requires a lot of sensitivity to just talk about the issue – a lot of sensitivity,” she said.

The Senate will debate legislation that would have the Constitution define marriage as the union between a man and a woman early next month, Majority Leader Bill Frist said on CNN’s “Late Edition.”

President Bush supports the amendment, but Vice President Dick Cheney does not. Cheney’s daughter, Mary, is a lesbian and has been speaking out against the marriage amendment as she promotes her new book, “Now It’s My Turn.”

Mary Cheney wrote that she almost quit working on the Bush-Cheney campaign in 2004 because of Bush’s position on gay marriage. Asked Sunday about reports that White House political adviser Karl Rove and other Republicans want to use the issue to mobilize conservatives for the midterm election, she said she hoped “no one would think about trying to amend the Constitution as a political strategy.”

“I certainly don’t know what conversations have gone on between Karl and anybody up on the Hill,” Cheney added in her appearance on Fox. “But you know, what I can say is look, amending the Constitution with this amendment, this piece of legislation, is a bad piece of legislation. It is writing discrimination into the Constitution, and, as I say, it is fundamentally wrong.”

But Frist said he would defend the amendment even to Dick Cheney.

“I basically say, Mr. Vice President, right now marriage is under attack in this country,” Frist said on CNN. “And we’ve seen activist judges overturning state by state law, where state legislatures have passed laws defining marriage between a man and a woman, and that’s being overturned by a handful of activist judges around the country. And that is why we need an amendment to come to the floor of the United States Senate to define marriage as that union between one man and one woman.”