Big business has ratcheted up its objections to proposals that would make it harder to vote, with several hundred companies and executives signing a new statement opposing “any discriminatory legislation."

The letter, published Wednesday in The New York Times and The Washington Post, was signed by companies including Amazon, Google, Starbucks and Bank of America, and individuals such as Warren Buffett and Michael Bloomberg, plus law firms and nonprofit groups.

It was the largest group yet to join in protests against Republican efforts to change election rules in states around the country.

“Voting is the lifeblood of our democracy and we call upon all Americans to join us in taking a nonpartisan stand for this most basic and fundamental right of all Americans,” the letter reads. “We all should feel a responsibility to defend the right to vote and oppose any discriminatory legislation or measures that restrict or prevent any eligible voter from having an equal and fair opportunity to cast a ballot."

Many of the signers have been loyal donors to Republican political campaigns.

The letter is a direct challenge to Republican officials who have pushed for changes in state voting laws, citing former President Donald Trump's unproven claim that he lost the November election because of fraud. At the same time, Democrats in Congress propose to overhaul federal voting law in a way that Republicans argue would interfere with state control of elections and hurt the GOP.

There were some notable absences from Wednesday's letter, including Delta Air Lines and the Coca-Cola Co. Both companies' CEOs had previously criticized a new Republican-backed law in Georgia that critics say will restrict voting.

A Delta spokeswoman declined to comment beyond pointing to a March 31 statement in which CEO Ed Bastian called the Georgia law unacceptable and said it could make voting harder for Blacks and other people of color. A Coca-Cola spokeswoman said the company had not seen the letter but that it stands by its support for “free and fair elections.”

The business community traditionally has steered clear of taking public positions on political or social issues. That history made it remarkable when, over the weekend, more than 100 corporate executives, academics and legal experts met online to discuss restrictive voting proposals, including the Georgia law.

Yale University management professor Jeffrey Sonnenfeld, who helped organize the call, said the executives discussed withholding campaign contributions to elected officials who try to restrict voting, and even withholding investment from states that adopt such laws - although the latter seemed to draw less support, he said.

Earlier this month, 72 Black business leaders signed a letter published in the Times that urged corporate leaders to publicly oppose any laws that restrict voting by Blacks.

This week, the leaders of three dozen major Michigan companies, including General Motors and Ford, objected to Republican-sponsored election bills that would make it harder to vote in Michigan and other states.

More than 350 different voting bills are under consideration in dozens of states, according to a tally from the Brennan Center for Justice, a public-policy think tank. On Tuesday Arkansas was among the latest to approve changes to its election laws, including restrictions on outside polling places and on absentee ballots.

The pushback against GOP-backed voting laws drew a warning this month from Senate Republican leader Mitch McConnell, who told business leaders to “stay out of politics." He warned companies not to get involved in upcoming debates in Congress over environmental policy and gun violence.

McConnell backtracked a few days later, admitting “I didn’t say that very artfully." Instead, he accused business leaders of not reading the Georgia bill before condemning it.