Carolyn Kaster / AP Trent Franks on Capitol Hill in Washington, Tuesday, June 18, 2013.

In what some conservatives are calling the most important abortion measure to be considered by Congress since 2003’s partial birth abortion ban, the House today passed a bill that would make it illegal to terminate pregnancies after 20 weeks. The bill, which passed 228-196, is not expected to have an impact on federal abortion law. The Senate is unlikely to take up the bill and the White House has already threatened to veto such legislation if it ever lands on President Obama’s desk.

Championed by Arizona Rep. Trent Franks, the Pain-Capable Unborn Child Protection Act is symbolic. Republican-controlled state legislatures across the country have passed similar legislation, which has been sometimes struck down by the courts or tangled in ongoing litigation. The House effort is meant to add federal firepower to the slow and steady quest to challenge and eventually overturn the 40-year-old Roe v. Wade Supreme Court ruling, which held that abortion should be legal until a fetus is viable, generally understood to be around 24 weeks. Roe opponents say their momentum is building, especially on the heels of the high-profile murder trial of Philadelphia abortion doctor Kermit Gosnell, who performed illegal and sometimes gruesome late-term abortions and was recently sentenced to life in prison.

Not all Republicans endorsed the idea of bringing the 20-week abortion ban to a floor vote. Rep. Charlie Dent of Pennsylvania, told the New York Times that doing so was a “stupid idea” that risks alienating voters with more moderate views on abortion at a time of economic uncertainty. The measure attracted six Democratic votes; six Republicans voted against the bill.