WASHINGTON (TheBlaze/AP) — The abortion wars return to Congress in a big way with House legislation to ban almost all abortions after a fetus reaches the age of 20 weeks. The proposal — a controversial one — has fired up both sides of the debate.

The legislation expected to pass the Republican-controlled House as early as Tuesday has no chance of becoming law in the near future: The Democratic-led Senate will ignore it and the White House has issued a veto threat. But the measure gives social conservatives a rare chance to promote their anti-abortion agenda and lays the groundwork for what could be a future challenge to the 1973 Supreme Court decision that confirmed a woman’s right to late-term abortions.

The two sides in the abortion debate agreed at least on the importance of the measure.

National Right to Life Committee legislative director Douglas Johnson said it was the “most significant piece of pro-life legislation to come before the House since the Partial-Birth Abortion Ban Act” that was enacted in 2003. Rep. John Conyers of Michigan, top Democrat on the House Judiciary Committee, said the bill “clearly is an attack on women’s constitutional right to choose and is one of the most far-reaching bans on abortion this committee has ever considered.”

The legislation defies the 1973 ruling which made most abortions legal up to the point that a fetus is viable, generally considered to be at least 24 weeks.

Some 11 state legislatures have passed similar measures. Several have been challenged in court and a federal court last month struck down a slightly different Arizona law that banned abortion after 20 weeks of pregnancy. Anti-abortion groups said the time frame in the House bill and other state laws, which ban abortion 20 weeks after conception, is equal to 22 weeks of pregnancy.

The sponsors of the bill, named the Pain-Capable Unborn Child Protection Act, also cited evidence — which opponents say is disputed — that fetuses can feel pain after five months.

House GOP leaders, stymied by a Democratic Senate and a Democrat in the White House, have chosen to focus on economic issues rather than contentious social topics such as abortion. “Jobs continue to be our number one concern,” House Speaker John Boehner, R-Ohio, said last week when asked about the abortion bill. But he said that “after the Kermit Gosnell case and the publicity that it received, I think the legislation is appropriate.”

Gosnell was a Philadelphia abortion provider who last month received a life sentence for what prosecutors said was the murder of three babies delivered alive. The case energized anti-abortion groups, who said it exemplified the inhumanity of late-term abortions.

The original House bill, sponsored by anti-abortion leader Rep. Trent Franks, R-Ariz., was aimed only at the District of Columbia, but was expanded to cover the entire nation after the Gosnell case received national attention.

Pro-choice groups argued that the 20-week ban, in addition to being unconstitutional, would affect women just at the point of learning of a fetal anomaly or determining that the pregnancy could put the mother’s life in danger.

As introduced, the bill provided for an exception to the ban only in cases of a physical condition that endangers the life of the mother. In the Judiciary Committee last week, Republicans rejected Democratic attempts to include rape, incest and other health problems as grounds for exceptions.

But Franks, during debate on the rape exception, angered Democrats and drew unwanted publicity to the bill when he stated that cases of “rape resulting in pregnancy are very low.”

Franks later rephrased his remark, but GOP leaders rushed to impose damage control. A provision was inserted in the bill heading to the House floor including a rape and incest exception, and Franks, who heads the Judiciary subcommittee on the constitution and civil justice, was replaced as floor manager for the bill by Rep. Marsha Blackburn, R-Tenn., who is not a member of the Judiciary Committee.

Democrats had pointed out that every Republican on the Judiciary Committee that approved the anti-abortion bill was a man.

With the changes, said NARAL Pro-Choice America President Ilyse Hogue, “the GOP is desperately trying to hide that the party has a deep hostility to women’s rights and freedom.”