Pennsylvania on Monday joined a growing number of states with Republican-led legislatures seeking to effectively ban abortion, as two lawmakers unveiled so-called heartbeat bills.

Sen. Doug Mastriano (R., Franklin) and Rep. Stephanie Borowicz (R., Clinton) made good on their promise to introduce a measure they said was aimed at giving a more conservative U.S. Supreme Court the opportunity to overturn Roe v. Wade, the 1973 decision that legalized abortion.

Senate Bill 912 and House Bill 1977 would prohibit abortion once a fetal heartbeat can be detected, typically at about six weeks’ gestation.

Doctors and reproductive rights advocates argue that the proposals amount to a near-ban, since they would prohibit abortions before many women know they are pregnant.

“When you hear a baby’s heartbeat, everything changes,” Borowicz said during an emotional news conference at the Capitol. “If you can be declared dead when the heart stops, why not declared alive when it starts?”

Borowicz and Mastriano held the news conference in a Capitol media center packed with anti-abortion supporters. On stage, Mastriano and Borowicz were flanked by a several dozen state legislators, as well as constituents, including children who held placards that read, “Hear a Heartbeat. Hear Him.”

Gov. Tom Wolf, a Democrat, has vowed to veto any such bill. If the legislature overrides him, it would certainly be tied up in court challenges.

“This bill is nothing but another unconstitutional attempt to ban abortion in Pennsylvania,” said Ashley Lenker White, executive director of Planned Parenthood PA Advocates. “It’s a waste of taxpayer time and money."

Several states have passed a variety of similar laws, driven in part by President Donald Trump’s appointment of two conservative justices to the Supreme Court. In general, all have been struck down as unconstitutional.

Mastriano framed his support for the measure as an extension of his three decades of military service.

“I refuse to surrender. I‘m going to fight this to my dying breath,” he said. "This is a fight worth fighting, and I‘m going to fight till the end. We are not going to win any victories if we capitulate.”

In a statement, Women’s Law Project senior staff attorney Susan J. Frietsche excoriated the proposed measures: “Even the anti-abortion lawyers who write these boilerplate bills concede they’re blatantly unconstitutional.... It’s shocking how some lawmakers are willing to exploit the lives of their constituents to win some cheap political points with anti-abortion donors and lobbyists.”

Kathy Barnette, a Fox News personality who has become a spokeswoman for the anti-abortion movement, injected the volatile subject of rape and racism into the debate. She said she was conceived when her mother was raped.

Barnette criticized abortion rights as an attempt to annihilate black people.

“Lynching got nothing on Planned Parenthood,” Barnette said. “What slavery could not do in 200 years, and what Jim Crow laws could not do in 100 years, abortion and organizations like Planned Parenthood have succeeded in annihilating whole generations of black people.”

Earlier this month, just six months after it was signed into law, Georgia’s heartbeat bill was struck down in federal court. And a divided U.S. appeals court ruled that Ohio could not enforce a 2017 law banning abortions when medical tests show that a fetus has Down syndrome.

Public support for legal abortion remains high. Currently, 61% of Americans polled say abortion should be legal in all or most cases, while 38% say it should be illegal in all or most cases. Meanwhile, the U.S. abortion rate continues a long-term downward trend, according to the Guttmacher Institute. In 2017, the rate dropped to 13.5 abortions per 1,000 women ages 15 to 44, down from 14.6 in 2014. The peak was 29.3 in 1980.