U.S. President Joe Biden on Tuesday assailed Republican-led states pushing to tighten voting rules, calling it an "unfolding assault … on liberty."
Republicans say they are tightening voting rules so that no election fraud occurs in the future and that Americans can have confidence that votes are fairly counted.
But Biden, in perhaps the most emotional speech of his six-month presidency, contended that the 28 laws already adopted in 17 states "make it harder for Americans to vote."
"This is election subversion," he declared. "It's simply unconscionable."
Without naming him, Biden rebuked former President Donald Trump for his continuing claims that he was cheated out of another four-year term in the White House by voting and ballot-counting fraud in last November's election.
"The big lie is just that, a big lie," Biden declared to the loud applause of supporters gathered at the National Constitution Center in Philadelphia.
Biden chose the city for the voting rights address because it is the cradle of American democracy: It's where the country's Founding Fathers first declared their independence from England in 1776.
"In America, if you lose, you accept the results," Biden said of Trump, who skipped Biden's January inauguration and has yet to publicly declare that Biden won the election.
Biden called again for the Senate to pass voting-rights legislation already approved by the House of Representatives that would nationalize congressional and presidential election rules, overriding the newly enacted state restrictions that Biden and Democratic lawmakers say would especially inhibit voting by minorities, who most often vote for Democrats.
WATCH: Biden pushes for voting law
But as it stands, the legislation has little chance of passage in the 100-member Senate, split evenly between 50 Democrats and 50 Republicans. Republicans recently blocked debate on the measure.
Biden emotionally implored lawmakers, saying, "Stand up, for God's sake, and protect the right to vote."
For the moment at least, the United States will head into next year's congressional elections with no change in the long-standing practice whereby each of the 50 states sets its own rules on voter registration, voting hours, mail-in ballots and more.
In advance of Biden's trip to Philadelphia, the White House said that "an alarming number of states … are erecting new barriers to voting, with additional barriers threatened elsewhere."
Republicans say the laws are necessary to ensure election integrity and prevent fraud, although there were almost no irregularities found in the 2020 voting, and not anywhere close to enough to have upended Biden's victory.
In the latest state political voting law confrontation, Republican legislators in the southwestern state of Texas, the country's second most populous, are attempting to push through new restrictions.
Democratic lawmakers first blocked passage of the measure in May by walking out of a legislative session to deny Republicans a quorum for a vote. This week, they fled the state during a special session to visit national Democratic lawmakers in Washington and push for countrywide election rules. The Texas Democrats said they plan to stay away from their home state until the legislative session ends in early August.
The White House said other recent events are undermining voting rights, including what it called the "sham 'audit' in Arizona" of the 2020 presidential vote in a state that Biden won over Trump. State Republican officials in Arizona authorized the new recount there, looking for vote-counting irregularities, although official tallies were completed months ago with no evidence of consequential fraud that would have overturned Biden's victory in the state.
The White House contended that the Arizona Legislature "gave conspiracy theorists access to 2020 election ballots without consistent rules or supervision," eroding "faith in the electoral process."
It said a recent Supreme Court voting rights decision "greatly weakened existing federal tools to combat regressive voting laws."
The government's Justice Department recently sued the state of Georgia in an attempt to block its election changes, and Biden named Vice President Kamala Harris to lead his administration's fight for voting rights.
She said the Texas Democratic lawmakers "have shown great courage, and certainly great conviction and commitment" in leaving the state to block passage of the proposed Republican election law changes.
White House press secretary Jen Psaki said Monday that Biden is redoubling "his commitment to using every tool at his disposal to continue to fight to protect the fundamental right of Americans to vote."
But congressional legislation remains unlikely, with Republicans opposed to the Democratic-proposed nationalization of elections, and at least two Democratic senators opposed to changing legislative voting rules to allow passage of election rules changes with a simple majority vote.