Even before Georgia's new abortion legislation becomes law, lawyers are preparing a constitutional challenge.

“If the governor signs this bill into law, the ACLU of Georgia will see him in court,” ACLU Georgia Legal Director Sean Young said during an interview Friday afternoon.

Young said his office will seek a permanent injunction with the U.S. District Court for the Northern District of Georgia to block the law from being enforced.

“Under 50 years of U.S. Supreme Court precedent, Georgia's abortion ban is blatantly unconstitutional,” Young said of state legislation, passed but yet to be signed, that bans abortion after six weeks of pregnancy. “Every federal court that has heard a challenge to such a ban has struck it down.”

“The law goes into effect in January 2020,” Young added. “We fully expect to be filing a lawsuit well in advance of that date.”

House Bill 481 bans abortion at six weeks of pregnancy—meaning four weeks from conception, or two weeks after a missed period, which could be before a woman knows she's pregnant, it has been noted. The law would make abortion after six weeks a crime for a doctor or a pregnant woman—unless she can provide a police report of rape or a medical diagnosis showing her life is threatened or the fetus can't survive. Gov. Brian Kemp spoke in favor of the bill both before and after it passed both the Georgia House of Representatives and the Senate—and the House again with revisions last month.

Candace Broce, director of communications and deputy executive counsel to Kemp, said Friday that all legislation passed this year is still under review.

“The Governor has until May 12 to sign, veto, or decide to take no action on such legislation,” Broce said. “At this time, there is no additional information to provide on any specific measure.”

Once the bill becomes law, the task of defending it will fall to Attorney General Chris Carr's office. His spokeswoman said she is not able to make any forward looking statements.

Proponents call the new law a “heartbeat bill” because it's timed around the first signs of an embryonic pulse. Opponents say even the name is wrong because the timing comes before the formation of a heart, when a pulselike sound can be heard only with a vaginal ultrasound.

Several other states have recently passed or are considering similar restrictions. The U.S. Senate is now considering a 20-week abortion ban, based on the belief that a fetus at that stage can feel pain. Georgia already has a 20-week abortion ban, signed into law by Gov. Nathan Deal in 2012.

Until now, abortion restrictions upheld by the courts have been based on whether a fetus could survive outside a uterus, Young said. The viable gestational age has moved earlier in recent years with advances in medical care, but both sides of the debate put it well beyond 20 weeks.

Legislators in Georgia and other states speaking in support of six-week bans have expressed the hope that their bill could be the one that leads the U.S. Supreme Court to overturn the landmark 1973 decision in Roe v. Wade, which ruled that unduly restrictive abortion regulation is unconstitutional.

“This is a straightforward legal issue,” Young said. But, he added, “As a lawyer, I would never predict what a court will do.”