U.S. Sen. Cory Gardner (R-CO) voted in favor of a bill Monday that would have banned abortions after 20 weeks and threatened doctors who perform those abortions with up to five years in jail.

The so-called “Pain-Capable Unborn Child Protection Act”, which passed in the House last October, failed as expected in the U.S. Senate, where it would have needed 60 votes to pass.

Gardner has been an adversary of reproductive rights throughout his political career.

Since he was first elected to Congress as a Representative in 2010, Gardner has voted to defund Planned Parenthood a total of nine times, and during his 2014 Senate campaign, Gardner called the conversation surrounding his record on abortion and birth control access a distraction.

His anti-abortion stance fueled his early political career as well, and some believe that his support for personhood, or the conferring of individual legal rights to a fertilized human egg and fetus, played a key part in his eventual success.

The bill, which was defeated by Senate Democrats, was based on the scientifically unproven concept of fetal pain.

Many doctors have rejected the claim that fetuses have the ability to feel pain after 20 weeks of gestation, citing a wide-ranging 2005 study that found fetuses don’t develop the neurological wiring that allows them to feel pain until the third trimester, at about 29 weeks. The American Congress of Obstetricians and Gynecologists said in 2013 that no subsequent research had contradicted that study.

Very few abortions – about one percent – take place after 20 weeks, and are typically due to severe fetal abnormalities.

The legislation exempted cases of rape and incest, as well as abortions necessary to save the life of the mother. But the failed bill did not include exemptions for the health of the mother or for fetal abnormalities, which often can’t be detected until after 20 weeks.

One Colorado lawmaker, speaking from experience, called banning late-term abortions “cruel.”

State Rep. Dafna Michaelson Jenet (D-Commerce City) spoke publicly her abortion experience for the first time in a Denver Post op-ed following the House’s vote on the bill last October, in which she explained how complications with her pregnancy led her to have a late-term abortion rather than carry an unviable pregnancy to term.

Gardner’s office did not immediately respond to a request for comment.