The US House of Representatives has given final congressional approval to a bill to bolster supreme court security, ahead of an anticipated ruling curtailing abortion rights and in light of the arrest of a man charged with attempting to murder Brett Kavanaugh, a member of the court’s conservative majority.

The legislation, which had already cleared the Senate, passed the House on a 396-27 vote. Joe Biden is prepared to sign it into law. It will expand police protection to families of justices and senior court officials.

The House Republican leader said the bill would protect justices from “leftwing radicals”.

A prominent Democrat said family members of court clerks and officials were also under threat, from “rightwing activists”.

The court is due to rule in a major abortion case from Mississippi. A leaked draft opinion showed the conservative majority poised to overturn the 1973 Roe v Wade ruling that legalized abortion. Protests have ensued outside some justices’ homes.

Last week, a California man carrying a handgun, ammunition, a crowbar, pepper spray and zip-tie handcuffs was arrested outside Kavanaugh’s home in Maryland.

Republicans have led calls for improved protection but some progressives have contrasted such eagerness to act with many Republicans’ refusal to consider gun reform, even in the wake of a series of mass shootings.

On the House floor on Tuesday, Veronica Escobar, a Democrat from El Paso, Texas, said: “It is incredible to stand here and listen to our Republican colleagues talk about the risks and the dangers that exist to the supreme court.

“I want to know where they were when the risks and the dangers existed in my community. In El Paso, Texas, where 23 innocent people were slaughtered by a white supremacist with an AK-47 [in 2019]. Where were they then?

“How about Uvalde? Where were they then? How about every other mass shooting? Buffalo, you name it.”

Nineteen children and two teachers were killed in Uvalde last month. Also in May, 10 people died in a racist attack at a supermarket in Buffalo, New York.

Referring to gun reforms passed by the House but with no chance of passing the Senate, Escobar said: “Last week, we brought to the floor legislation intended to protect millions of Americans, especially including children.

“The vast majority of our Republican colleagues voted against those protections for vulnerable people who don’t have access to 24-hour, round-the-clock US marshals protection. Who don’t have access to round-the-clock 24/7 police protection, which supreme court justices have today.

“Supreme court justices have far more protection than members of Congress do. But more importantly [they have more protection] than those innocent lives that were taken in innumerable cities across America.”

The US justice department is already providing additional support to court police.

In the Kavanaugh case, Nicholas John Roske, 26 and from Simi Valley, California, was dressed in black when he arrived by taxi outside Kavanaugh’s home around 1am last Wednesday. According to court documents, he spotted two US marshals guarding the house and walked in the other direction, calling 911 to say he was having suicidal thoughts and planned to kill Kavanaugh.

Roske said he had found the address on the internet.

On Tuesday the House Republican leader, Kevin McCarthy, greeted passage of the bill by saying: “We are sending a clear message to leftwing radicals: you cannot intimidate supreme court justices.”

House Democrats had wanted to add protections for families of clerks and other court employees who, in the words of Ted Lieu, a congressman from California, “are getting threats from rightwing activists”.

But Senate Republicans objected.

“The security issue is related to supreme court justices, not the nameless staff that no one knows,” the minority leader, Mitch McConnell, said on Monday.

Lieu said measures to protect families of clerks and other employees would be considered separately.

The federal judiciary is calling for separate legislation to offer more protection for judges. The US marshals service said judges were subject to 4,511 threats and inappropriate communications last year.