You may have heard that abortion has been a trending issue in Congress this week. Here's why.

So what happened?

On Thursday, House Republicans passed a rewritten version of an anti-abortion bill following last-minute inter-party disputes over what some saw as prohibitive, restrictive language.

The passage of the new bill, which would block nearly all taxpayer-funded abortions, came less than 24 hours after House Republicans abruptly withdrew the original bill from the floor late Wednesday night amid concerns from women in the House GOP caucus that harsh stipulations would push away valuable, younger women voters.

Why did this come up?

Thursday’s vote came alongside the annual March for Life demonstration, which typically draws thousands of anti-abortion protesters to the Capitol on the anniversary of the landmark US Supreme Court case Roe v. Wade, which secured women the constitutional right to an abortion up to about 24 weeks. The 24-week threshold has since been the determined point before which a fetus cannot feel pain. The original House bill, sponsored chiefly by Rep. Trent Franks (R-Ariz.) and known as the Pain Capable Unborn Child Protection Act, would have redrawn that cut-off to 20 weeks, with rape and incest cases exempted only if they were reported to police first. Abortion rights advocacy groups were quick to point to Justice Department statistics estimating that nearly 70 percent of rapes go unreported.

The bill’s sponsors honed in on the importance of stopping money under Obamacare insurance plans funding abortions––a provision the bill would block.

“Abortion is not health care. It’s a brutal procedure that ends live of unborn children,” said Rep. Joseph Pitts (R-Pa.) on the House floor.

“I urge my colleagues to stand with the hundreds of thousands of people out on the Mall right now by voting for this bill,” added House Majority Leader Kevin McCarthy (R-Calif.).

What exactly are late-term abortions?

Another burning, controversial issue that the bill addresses is late-term abortions, or the practice of late termination of a pregnancy, when the fetus is more developed and potentially “viable,” or able to survive outside of the mother’s womb. But opponents dispute the premise that a fetus can feel pain at or around the 20-week mark. In previous legislative anti-abortion efforts, the American Congress of Obstetricians and Gynecologists have maintained that such claims are “not based on sound science,” and the American Medical Association’s online ethics journal has deemed them “scientifically ungrounded.”

Still, the issue of later term abortions is an uncomfortable one––arguably, for anyone regardless of political standing. The later it gets, the more the fetus resembles a living, breathing human. The United States, it turns out, is one of seven countries that even allows late terminations, although research indicates that the majority­­ of abortions––98.5 percent according to the Guttmacher Institute––occur before the 20-week mark. Additionally, a large portion of late-term abortions occur when wanted pregnancies go wrong.

But at what point does a fetus become a potential citizen protected and cared for by the state and an entity out of the woman’s control? According to pro-life initiatives, the 20-week point is the fulcrum. Over the past five years, some 12 states have passed similar 20-week abortion bans thanks to efforts and law-writing assistance from anti-abortion rights organizations like Americans United for Life. But at the Capitol Thursday, even thousands of pro-lifers marching on Congress’ doorstop couldn’t persuade conservative representatives to support similar legislation.

This is a battle within the Republican Party.

Perhaps the most interesting piece of this story is what was revealed about the Republican Party itself, and its inward perceptions and concerns around its newfound power station in the current Congress. Late Wednesday night, House Republicans were forced to rescind the original bill after female Republican legislators refused to endorse a bill whose harsh laws could ostracize younger female voters. The move illustrated the balancing act legislators must perform while attempting to uphold abortion restrictions central to conservative values while also appealing to younger women voters among whom such restrictions are unpopular.

The passage of Thursday’s bill in conjunction with the March for Life is largely a symbolic one. On the off chance that it makes it through the Senate without a Democratic filibuster, it will likely die on President Obama’s desk with a veto. But it remains an indicator, no doubt, of what kinds of legislating Republicans intend to do moving into 2015.

“This march is part of a larger one, and our destination is clear: to secure and protect the rights of every unborn child,” said House Speaker John Boehner (R-Ohio) in response to the bill. “When there is disagreement, we should pause and listen closely. When there is movement, we should rejoice, and the House’s vote to ban taxpayer funding of abortion is cause for doing so.”