President Joe Biden used the 100th anniversary of Tulsa’s race massacre to make a plea for sweeping legislation in Congress to protect the right to vote as Republican-led governments in a number of states pass restrictions making it tougher to cast ballots.

Mr Biden, marking the centennial in Oklahoma called out lawmakers in Congress – including two senators in his own party – for holding up action on voting bills. Invoking the words of late civil rights activist John Lewis, Mr Biden said the right to vote is “precious” and must be protected. He vowed that June will be a “month of action” as Congress considers the legislation.

“We’re not giving up,” Biden said of the bill. “I’m going to fight like heck with every tool at my disposal for its passage.”

Republican legislators in state capitols across the US are pushing what experts say is an unprecedented wave of bills aimed at restricting access to the ballot box. While Republicans say the bills are aimed at preventing voter fraud, Democrats contend the measures are aimed at undermining minority voting rights. 

Mr Biden addressed the federal voting rights legislation at an event marking the 100th anniversary of the Tulsa race massacre, in which a white mob looted Tulsa’s Greenwood district, which was known as “Black Wall Street.”

As many as 300 black Tulsans were killed, and thousands of survivors were forced for a time into internment camps. Mr Biden said the nation must acknowledge the long-forgotten chapter of history to heal from it, and he pledged action on key issues confronting black Americans, including police misconduct and restrictions on voting rights.

“We can’t just choose what we want to know, and not what we should know,” Mr Biden said. “I come here to help fill the silence, because in silence wounds deepen.”

Despite Mr Biden’s pledge to keep fighting to pass legislation protecting voting rights, he acknowledged on Tuesday that his biggest obstacle may lie within his own party.

Mr Biden called out two fellow Democrats in explaining why he hasn’t enacted some of the most ambitious elements of his agenda, noting that slim majorities in the House and evenly divided Senate have hamstrung legislative negotiations around key issues.

Responding to critics who question why he hasn’t been able to get a wide-reaching voting rights bill passed, Mr Biden said, “Well, because Biden only has a majority of effectively four votes in the House, and a tie in the Senate – with two members of the Senate who voted more with my Republican friends.”

It appeared to be a veiled reference to Democratic senators Joe Manchin and Kyrsten Sinema, both of whom have frustrated Democrats with their defence of the filibuster. 

But it’s not just Mr Manchin and Ms Sinema who oppose doing away with the filibuster – up to 10 Democratic senators are reluctant to change the rules even for legislation like the voting rights bill. Mr Biden himself has not said he wants to end the filibuster.

It’s unclear whether Mr Biden’s comments will change the views of any senators, who are facing tough choices ahead.

Senate Majority Leader Chuck Schumer told colleagues he would be bringing the voting rights bill to a vote the week of June 21, in effect testing where senators stand.

He wrote to colleagues last week, warning them to brace for the month ahead.