The founder of Amazon, Jeff Bezos, and his wife MacKenzie, have pledged $2.5 million to the campaign for marriage equality in Washington state. The donation makes them among the largest financial backers of marriage equality in the country.

As Michael D. Shear reports in the New York Times, through their gift, the couple has doubled the money available to the proponents of Referendum 74, which would legalize same-sex marriage in Washington by affirming a law that passed the legislature in February.

The marriage equality bill passed the legislature with the enthusiastic support of Governor Christine Gregoire, but opponents quickly gathered sufficient signatures to subject the law to a referendum in November.

Zach Silk, campaign manager for Washington United for Marriage, hailed the gift as a game-changer. "To get this from a straight, married couple sends a powerful message that marriage is seen as a fundamental question of fairness," he said.

Bezos, who founded Amazon.com in 1994 and remains its president, now tops a growing list of heterosexual business executives who have donated to the marriage equality movement. Earlier Bill Gates and Steven A. Ballmer of Microsoft each gave $100,000 to the Washington referendum campaign.

Other heterosexuals who have been at the forefront of helping fund the marriage equality movement include Paul Singer, founder of the hedge fund Elliott Management, who donated more than $1 million to the effort to achieve marriage equality in New York, and who recently donated another $1 million to establish a pro-gay Republican pac; Rob Reiner, who co-founded the American Foundation for Equal Rights to fund the federal court challenge to Proposition 8; and Hollywood figures such as Brad Pitt, who made generous contributions to the attempt to defeat Proposition 8, which banned same-sex marriage in California in 2008.

Still, openly gay philanthropists such as Tim Gill, Jon Stryker, David Geffen, David Bohnett, Jonathan D. Lewis, James C. Hormel, Bruce Bastian, and Chris Hughes and Sean Eldridge have undoubtedly made the largest contributions to the marriage equality movement.

The Bezos donation is especially welcome since opponents of marriage equality, who have never lost at the ballot box, are now mobilizing in Washington and in the three other states where marriage issues will be on the ballot in November: Maryland, Maine, and Minnesota.

Those opposed to marriage equality in Washington have said they intend to raise as much as $4 million to defeat it and overturn the legislation.

Shear explains how the Bezos gift came about. The entrepreneur was approached via e-mail on July 22 by Jennifer Cast, one of Amazon's earliest employees and a lesbian mother of four children who is now a fund-raising chairwoman of the Referendum 74 effort.

In her e-mail, Cast asked Bezos to understand the importance of the issue to her and her longtime partner.

"I want to have the right to marry the love of my life and to let my children and grandchildren know their family is honored like a 'real' family," she wrote. "We need help from straight people. To be very frank, we need help from wealthy straight people who care about us and who want to help us win."

Shear reports that Cast said she had no idea how Bezos would respond. Though they had worked closely together when Amazon had only a few dozen employees, she left the company in 2001. She said she had never talked with him about same-sex marriage.

In the e-mail, however, she described in detail the pain she endured as a young adult and the difficulties she faced publicly acknowledging her sexuality. At the end, she pointedly asked him to donate between $100,000 and $200,000 to the referendum cause.

"Jeff, I suspect you support marriage equality," she wrote. "I beg you not to sit on the sidelines and hope the vote goes our way. Help us make it so."

Two days later, on Tuesday, July 24, Cast received a reply while in a car with her family. She said she had to read it out loud twice to make sure she had read it right.

"Jen," the e-mail said, "this is right for so many reasons. We're in for $2.5 million. Jeff & MacKenzie."

In the video below, Seattle hip-hop artist Macklemore explains why he is also in support of marriage equality.