It's been called a groundbreaking law, but a measure approved in Nebraska last week that changes the rationale for abortion bans probably won't go into effect anytime soon — if ever.

Instead, abortion opponents are hoping it will become the most important case on abortion to reach the U.S. Supreme Court in recent memory. Even they acknowledge the ban on abortions at and after 20 weeks of pregnancy won't see the light of day unless the high court rules that it is constitutional.

Mary Spaulding Balch, legislative director for National Right to Life, said a court injunction will likely prevent the implementation of the law. The measure passed last week by Nebraska's nonpartisan Legislature and signed into law by Republican Gov. Dave Heineman is scheduled to take effect in October.

Lower courts have no precedent to support the law, which bases the new restrictions on the assertion that fetuses feel pain.