A Catholic advocacy group has written to the bishops of Massachusetts asking them to excommunicate Governor Maura Healey following her signing of legislation into effect to remove restrictions on late-term abortions, which would allow for abortion up to birth.

The Prioritizing Patient Access to Care Act was passed by the Senate on July 21 and signed on August 10, with Healey stating that it would continue the state’s efforts to have “the strongest abortion protections in the country”. Previously, Massachusetts allowed abortion before 24 weeks of pregnancy provided a physician deemed it necessary.

Kelsey Reinhardt, head of the advocacy group Catholic Vote, said as she published the open letter that she was asking for clarification on whether Governor Healey was excommunicated.

The letter, addressed to the bishops, read: “You have yourselves described the consequences in terms that leave no room for ambiguity: this legislation opens the door to the abortion of unborn children until the moment of birth. You have named it for what it is. We are grateful for that clarity. We are writing to ask you to follow that clarity to its logical and canonical conclusion.

“The new law permits what no civilisation formed in the tradition of natural law and Christian revelation can permit without self-contradiction, which is the deliberate ending of a human life at its most defenceless, at the very threshold of birth.”

The letter argued that Healey was “not a bystander” and was the “necessary final act of a legislative process that cannot take legal effect without her”. “The Church’s law was written to account for exactly this kind of co-operation,” it read.

It cited canon 1397 §2 of the Code of Canon Law, which imposes an automatic excommunication on a person who procedures an abortion, stating that it “extends that same penalty to accomplices” if “without their assistance the offence would not have been committed”.

“The question before you is whether Governor Healey qualifies as an essential accomplice under this canon. We believe the answer is yes, but most importantly, we believe that such a conclusion can only be asserted beyond doubt by your authority.”

The letter also criticised the manner in which the law was signed, stating that it was “signed at a celebratory public event. She was met with applause. The ceremony was festive.”

Bishop Robert Barron also criticised the display, stating: “They were clapping and cackling with delight because what can only be called infanticide can now be practised with impunity in their state.”

“Please understand what this means. A fully-formed child, moments before exiting the birth canal, can be eviscerated, chopped into pieces, have its head crushed or skin burned off – all under the full protection of Massachusetts law,” the bishop said.

The signing of the legislation makes Massachusetts the 11th state, alongside Washington DC, with abortion up until birth. SBA Pro-Life America president Marjorie Dannenfelser called for an end to what she called the Republican Party’s “leave it to the states” position.

Dannenfelser said: “Without a minimum national standard, the United States remains one of only eight countries worldwide that allows abortion at any point in pregnancy. We must do all we can to turn the page on America’s ugly chapter of late-term abortion.”