With two new President Bush-appointed justices on the U.S. Supreme Court, Utah is preparing to spend up to $4 million to defend a proposed law banning abortions that it hopes will lead to the overturn of Roe v. Wade.

It's a gamble that some constitutional law scholars say is a losing bet because the prevailing court case on abortion isn't the 1973 decision on Roe v. Wade, which made abortion legalized nationwide. It's the 1992 opinion in a case called Casey v. Planned Parenthood.

That case allowed states to place some restrictions on abortion. But it also reaffirmed a woman's right to an abortion established under Roe v. Wade and said states couldn't place an "undue burden" on women seeking an abortion.

Even if both Bush-appointed justices John Roberts and Samuel Alito "were hellbent on overturning it, they don't have a fifth vote," said Pam Karlan, a constitutional law professor at Stanford University. "Right now, on the Supreme Court there are not five votes to overturn Planned Parenthood versus Casey. ... It's absolutely clear that the current court would not permit a state to ban all abortions."

Karlan and others say it's highly unlikely the Supreme Court would even hear the case.

"If all the lower courts agree that this is unconstitutional, then the Supreme Court would probably react cautiously and not take it," said Robert Bennett, a constitutional law scholar at Northwestern University.

But Utah lawmakers seem intent on giving it a try. The state House may vote as early as this week on a bill to ban abortions except in cases of rape, incest or if the health of the mother is threatened.

Originally, the bill would have made abortions illegal in Utah only if Roe v. Wade were overturned. It was written in response to South Dakota passing a law last year banning nearly all abortions in an attempt to give the U.S. Supreme Court a case on which to overturn Roe v. Wade. The South Dakota law was later rejected by voters, but lawmakers there are giving it another try this year.

The multistate effort to ban abortions worries abortion rights advocates.

"Despite South Dakotans' clear rejection of an abortion ban in 2006, anti-choice legislators in Utah and other states continue to show that there's no way to predict where and when they will overreach in their attempts to interfere in personal, private medical decisions," Nancy Keenan, president of NARAL Pro-Choice America, said in a statement.

Utah's Republican-controlled Legislature has indicated it doesn't want to wait for another state to challenge Roe v. Wade.

"Somebody's got to step up and be the leader," said the bill's sponsor, Rep. Paul Ray, R-Clearfield.

Ray's bill easily cleared a House committee last week and has the support of leaders in the House and Senate. In the past, Republican Gov. Jon Huntsman Jr. has said he supports restricting abortions.