Over 200 members of Congress have signed their names onto an effort to overturn two key abortion protections in the United States, marking the latest attempt by the GOP to take down the longstanding right.

The list includes 39 Republicans hailing from red states, most of which Donald Trump carried in 2016 in a surprise victory that has allowed him to appoint two new conservative justices to the Supreme Court. Another 168 politicians in the House have also signed, including two Democrats.

In the letter, the members call for a revisiting of Roe v Wade, the landmark Supreme Court decision establishing the right to an abortion, and, "if appropriate", to overrule the protection.

The letter comes as the Supreme Court considers a challenge to a Louisiana state law known as the “Unsafe Abortion Protection Act” that would require abortion providers to have admitting privileges at nearby hospitals, which supporters say would help assist with the “continuity of care” should an emergency arise.

But, just two doctors in the state have been able to receive a special designation required under the law. And, according to CBS News, one of those doctors has already stopped giving abortions, and the other has threatened to retire should the Supreme Court rule for the further restrictions on abortions.

In their amicus brief, the nearly 40 Republicans who signed their names to support the Louisiana law suggested that it illustrates that the American right to an abortion is unworkable.

The issue “illustrates the unworkability of the 'right to abortion' found in Roe v Wade”, the senators wrote.

Protests across US after abortion laws enforced Show all 20 1 /20 Protests across US after abortion laws enforced Protests across US after abortion laws enforced Missouri Thousands of demonstrators march in support of Planned Parenthood and pro-choice as they protest a state decision that would effectively halt abortions by revoking the license of the last center in the state that performs the procedure, during a rally in St. Louis, Missouri, May 30, 2019. (Photo by SAUL LOEB / AFP) (Photo credit should read SAUL LOEB/AFP/Getty Images) SAUL LOEB AFP/Getty Protests across US after abortion laws enforced Alabama MONTGOMERY, AL - MAY 19: Lindsey Shelton participates in a rally against one of the nation's most restrictive bans on abortions on May 19, 2019 in Montgomery, Alabama. Demonstrators gathered to protest HB 314, a bill passed by the Alabama Legislature last week making almost all abortion procedures illegal. (Photo by Julie Bennett/Getty Images) Julie Bennett Getty Protests across US after abortion laws enforced New York Alison Hickerson from New York City poses for a photo as she take part in a rally in front of the Middle Collegiate Church in the East Village of New York May 21, 2019. - Demonstrations were planned across the US on Tuesday in defense of abortion rights, which activists see as increasingly under attack. The "Day of Action" rallies come after the state of Alabama passed the country's most restrictive abortion ban, prohibiting the procedure in all cases, even rape and incest, unless the mother's life is at risk. Alabama is among about 14 states which have adopted laws banning or drastically restricting access to abortion, according to activists. (Photo by TIMOTHY A. CLARY / AFP) (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images) TIMOTHY A. CLARY AFP/Getty Protests across US after abortion laws enforced Georgia ATLANTA, GA - MAY 21: Melissa Simpson holds up her arm with "My Body My Choice" written on it during a protest against recently passed abortion ban bills at the Georgia State Capitol building, on May 21, 2019 in Atlanta, United States. The bill would ban abortion when a fetal heartbeat is detected. The Alabama abortion law, signed by Gov. Kay Ivey last week, includes no exceptions for cases of rape and incest, outlawing all abortions except when necessary to prevent serious health problems for the woman. Though women are exempt from criminal and civil liability, the new law punishes doctors for performing an abortion, making the procedure a Class A felony punishable by up to 99 years in prison. (Photo by Elijah Nouvelage/Getty Images) Elijah Nouvelage Getty Protests across US after abortion laws enforced Atlanta ATLANTA, GA - MAY 21: Women hold signs during a protest against recently passed abortion ban bills at the Georgia State Capitol building, on May 21, 2019 in Atlanta, Georgia. The Georgia "heartbeat" bill would ban abortion when a fetal heartbeat is detected. The Alabama abortion law, signed by Gov. Kay Ivey last week, includes no exceptions for cases of rape and incest, outlawing all abortions except when necessary to prevent serious health problems for the woman. Though women are exempt from criminal and civil liability, the new law punishes doctors for performing an abortion, making the procedure a Class A felony punishable by up to 99 years in prison (Photo by Elijah Nouvelage/Getty Images) Elijah Nouvelage Getty Protests across US after abortion laws enforced Alabama Pro-Choice protesters march through the streets of Birmingham, Alabama, during the March For Reproductive Freedom on May 19, 2019. - The state of Alabama passed a near-total abortian ban on May 14, 2019, one of the nation's most restrictive bans on abortions in decades. (Photo by Seth HERALD / AFP) (Photo credit should read SETH HERALD/AFP/Getty Images) SETH HERALD AFP/Getty Protests across US after abortion laws enforced Missouri ST LOUIS, MO - MAY 31: Pro-Choice supporters, along with Planned Parenthood staff celebrate and rally outside the Planned Parenthood Reproductive Health Services Center on May 31, 2019 in St Louis, Missouri. A judge has issued an order allowing Missouri's only abortion clinic to continue providing the service and maintaining their license until June 4. (Photo by Michael Thomas/Getty Images) Michael Thomas Getty Protests across US after abortion laws enforced Alabama Pro-Choice protesters march through the streets of Birmingham, Alabama, during the March For Reproductive Freedom on May 19, 2019. - The state of Alabama passed a near-total abortian ban on May 14, 2019, one of the nation's most restrictive bans on abortions in decades. (Photo by Seth HERALD / AFP) (Photo credit should read SETH HERALD/AFP/Getty Images) SETH HERALD AFP/Getty Protests across US after abortion laws enforced Georgia ATLANTA, GA - MAY 21: People hold signs during a protest against recently passed abortion ban bills at the Georgia State Capitol building, on May 21, 2019 in Atlanta, Georgia. The Georgia "heartbeat" bill would ban abortion when a fetal heartbeat is detected. The Alabama abortion law, signed by Gov. Kay Ivey last week, includes no exceptions for cases of rape and incest, outlawing all abortions except when necessary to prevent serious health problems for the woman. Though women are exempt from criminal and civil liability, the new law punishes doctors for performing an abortion, making the procedure a Class A felony punishable by up to 99 years in prison (Photo by Elijah Nouvelage/Getty Images) Elijah Nouvelage Getty Protests across US after abortion laws enforced Georgia ATLANTA, GA - MAY 21: Melissa Simpson snaps her fingers in support of a speaker during a protest against recently passed abortion ban bills at the Georgia State Capitol building, on May 21, 2019 in Atlanta, Georgia. The Georgia "heartbeat" bill would ban abortion when a fetal heartbeat is detected. The Alabama abortion law, signed by Gov. Kay Ivey last week, includes no exceptions for cases of rape and incest, outlawing all abortions except when necessary to prevent serious health problems for the woman. Though women are exempt from criminal and civil liability, the new law punishes doctors for performing an abortion, making the procedure a Class A felony punishable by up to 99 years in prison (Photo by Elijah Nouvelage/Getty Images) Elijah Nouvelage Getty Protests across US after abortion laws enforced Missouri Thousands of demonstrators march in support of Planned Parenthood and pro-choice as they protest a state decision that would effectively halt abortions by revoking the license of the last center in the state that performs the procedure, during a rally in St. Louis, Missouri, May 30, 2019. (Photo by SAUL LOEB / AFP) (Photo credit should read SAUL LOEB/AFP/Getty Images) SAUL LOEB AFP/Getty Protests across US after abortion laws enforced Washington, DC WASHINGTON, DC - MAY 23: People wait for the start of a news conference regarding womenâ€™s health care, on Capitol Hill May 23, 2019 in Washington, DC. The news conference was held to discuss the reintroduction of the "Women's Health Protection Act " and address the state-based attacks on abortion rights. (Photo by Mark Wilson/Getty Images) Mark Wilson Getty Protests across US after abortion laws enforced Louisiana Handsmaid themed protesters stand outside Jackson Square in the French Quarter of New Orleans, Louisiana, on May 25, 2019, to protest the proposed Heartbeat Bill that will ban abortion after 6 weeks in that state, scheduled for a vote on May 28. (Photo by Emily KASK / AFP) (Photo credit should read EMILY KASK/AFP/Getty Images) EMILY KASK AFP/Getty Protests across US after abortion laws enforced Louisiana Handsmaid themed protesters march down Bourbon Street in the French Quarter of New Orleans, Louisiana, on May 25, 2019, to protest the proposed Heartbeat Bill that will ban abortion after 6 weeks in that state scheduled for a vote on May 28. (Photo by Emily KASK / AFP) (Photo credit should read EMILY KASK/AFP/Getty Images) EMILY KASK AFP/Getty Protests across US after abortion laws enforced Missouri Thousands of demonstrators march in support of Planned Parenthood and pro-choice as they protest a state decision that would effectively halt abortions by revoking the license of the last center in the state that performs the procedure, during a rally in St. Louis, Missouri, May 30, 2019. (Photo by SAUL LOEB / AFP) (Photo credit should read SAUL LOEB/AFP/Getty Images) SAUL LOEB AFP/Getty Protests across US after abortion laws enforced Missouri TOPSHOT - Thousands of demonstrators march in support of Planned Parenthood and pro-choice as they protest a state decision that would effectively halt abortions by revoking the license of the last center in the state that performs the procedure, during a rally in St. Louis, Missouri, May 30, 2019. (Photo by SAUL LOEB / AFP) (Photo credit should read SAUL LOEB/AFP/Getty Images) SAUL LOEB AFP/Getty Protests across US after abortion laws enforced Missouri Pro-choice supporters and staff of Planned Parenthood hold a rally outside the Planned Parenthood Reproductive Health Services Center in St. Louis, Missouri, May 31, 2019, the last location in the state performing abortions, after a US Court announced the clinic could continue operating. - A US Court on May 31, 2019 blocked Missouri from closing the clinic. (Photo by SAUL LOEB / AFP) (Photo credit should read SAUL LOEB/AFP/Getty Images) SAUL LOEB AFP/Getty Protests across US after abortion laws enforced Washington, DC Abortion rights activists rally in front of the US Supreme Court in Washington, DC, on May 21, 2019. - Demonstrations were planned across the US on Tuesday in defense of abortion rights, which activists see as increasingly under attack. The "Day of Action" rallies come after the state of Alabama passed the country's most restrictive abortion ban, prohibiting the procedure in all cases, even rape and incest, unless the mother's life is at risk. Alabama is among about 14 states which have adopted laws banning or drastically restricting access to abortion, according to activists. (Photo by Andrew CABALLERO-REYNOLDS / AFP) (Photo credit should read ANDREW CABALLERO-REYNOLDS/AFP/Getty Images) ANDREW CABALLERO-REYNOLDS AFP/Getty Protests across US after abortion laws enforced Georgia ATLANTA, GA - MAY 21: Heather Masson, left, and Victoria Jernigan hold signs promoting a woman's right to choose during a protest against recently passed abortion ban bills at the Georgia State Capitol building, on May 21, 2019 in Atlanta, Georgia. The bill would ban abortion when a fetal heartbeat is detected. The Alabama abortion law, signed by Gov. Kay Ivey last week, includes no exceptions for cases of rape and incest, outlawing all abortions except when necessary to prevent serious health problems for the woman. Though women are exempt from criminal and civil liability, the new law punishes doctors for performing an abortion, making the procedure a Class A felony punishable by up to 99 years in prison (Photo by Elijah Nouvelage/Getty Images) Elijah Nouvelage Getty Protests across US after abortion laws enforced Alabama Cristina Castor (L) and Julian Kersh pose for a portrait in Ingram Park in Birmingham, Alabama, May 19, 2019 during the March for Reproductive Freedom. - "If this goes all the way and flips Roe v Wade at that point it just seems like where is this going to stop," Kersh said. The state of Alabama passed a near-total abortion ban on May 14, 2019 making it the most restrictive law in the United States. (Photo by Seth HERALD / AFP) (Photo credit should read SETH HERALD/AFP/Getty Images) SETH HERALD AFP/Getty

The Supreme Court is set to hear the case early this year, after the 5th Circuit Court of Appeals upheld key provisions of the law. The appeals court decision marked the first time a federal court had ruled in favour of such measures after a nearly identical law in Texas was struck down by the Supreme Court in 2016.

While the Supreme Court blocked the lower court ruling for the moment with the help of chief Justice John Roberts, it is not clear that it will not ultimately uphold the provision. Justice Roberts, in 2016, dissented with the majority opinion.

And, the conservative justice who joined liberals — Anthony Kennedy — to form a majority has now retired and been replaced by Brett Kavanaugh, who has expressed a willingness to undermine or discard the 2016 ruling out of Texas.

In response to the mostly Republican amicus brief, prominent Democrats and activists slammed the effort, and suggested that it has been clear that the GOP is intent on overturning abortion protections for .women.

"I won't hold my breath waiting for an apology from those who said that abortion rights supporters were being 'hysterical' when we decried Brett Kavanaugh's appointment to the Supreme Court as the possible end of Roe v Wade," Lauren Rankin, a womens' rights activist and writer, wrote on Twitter. "But here it is. They want to end legal abortion."

And Andrew Yang, a Democratic presidential candidate, responded to the news by calling for a codification of Roe v Wade, so that the Supreme Court could not undercut the right through state-level attacks. Much of the Democratic field has likewise called for a codification of the ruling.