What could happen if Roe v. Wade gets struck down?

Within hours after Justice Anthony M. Kennedy announced his retirement, the predictions were alternately dire or ecstatic: President Trump’s next Supreme Court pick could band with conservatives to overturn Roe v. Wade, the landmark 1973 ruling that legalized abortion nationwide.

What would happen then? And what has the nominee, U.S. Appeals Court Judge Brett Kavanaugh, indicated about his stance on abortion?

Regulating abortion would revert fully to state legislatures, many of which have become more conservative and have passed more than 400 laws that restrict access in the past six years alone.

There are four states where abortion would be banned as soon as Roe v. Wade were overturned: Louisiana, Mississippi, and North and South Dakota have enacted “trigger laws” with delayed effective dates. Nine states still have pre-Roe abortion bans on the books that never were repealed. Nine states have laws that explicitly protect abortion rights.

Many state laws are challenged in the courts for placing an “undue burden” on women who seek abortions, the current federal standard that the Supreme Court, with Kennedy in the plurality, established in 1992, in Planned Parenthood v. Casey. And some of those cases will land before the bench, where a new conservative justice may be more open to arguments that the state’s obligation to protect the health of mother and fetus outweighs a woman’s constitutional right to privacy.

The heated battle has been central to Democrats’ arguments against the confirmation of Kavanaugh. When former Senator Jon Kyl has been seated to fill the vacancy left by the death of Sen. John McCain of Arizona, the Republicans will restore their 51-49 majority in the chamber.

Republican Sens. Susan Collins (Maine) and Lisa Murkowski (Alaska) have reiterated their support for abortion rights and have shown their willingness to break with their party, particularly on defunding Planned Parenthood. And at least three Democrats facing reelection battles in states that Trump won may be willing to break with their party, too. Those three – Sens. Joe Manchin III (W.Va.), Heidi Heitkamp (N.D.) and Joe Donnelly (Ind.) – have met with the president at the White House and have been under pressure from liberal activists and their colleagues.

Supreme Court nominee Kavanaugh, 53, is expected to be questioned sharply about his views on abortion during his confirmation hearings, and a Washington Post-ABC News poll finds that 59 percent of Americans are in favor of hearing his opinion before he is confirmed.

Collins met with Kavanaugh in August and said he told her in the meeting, which lasted more than two hours, that he considers Roe v. Wade to be “settled law.” That could mean he sees the 45-year-old decision to be so woven into the fabric of the law that it cannot or should not be removed.

Abortion rights advocates are firmly opposed to his confirmation, however. In his 12 years as a federal judge, he has issued only one major ruling on the issue, a dissent in October in a case involving a pregnant immigrant teenager in federal custody.

The controversy “was Kavanaugh’s audition for the Supreme Court,” Fatima Goss Graves, president of the National Women’s Law Center, which supports abortion rights, told The Post. “After showing his hostility to abortion, he was added to Trump’s shortlist.”

Critics also point to his praise for William H. Rehnquist’s dissents in both Roe and Casey, saying they indicate the late chief justice’s resistance to a “free willing judicial creation of unenumerated rights.”

“Overturning Roe” would stay the rallying cry on both sides of the issue, but the antiabortion movement’s legal strategists plan to stick to their highly successful strategy of chipping away at abortion rights in the states, they told The Post's Amy Gardner. Forty-three states have some kind of limit on abortions, and at least six are down to one provider.

And there are two laws on hold by injunction and now in U.S. appeals court — one from Alabama and one from Texas — that would effectively outlaw the vast majority of abortions after 14 weeks, says Elizabeth Nash, who leads research on state policy on reproductive rights for the Guttmacher Institute.

Either could reach the Supreme Court in the next 18 to 24 months.