"I am writing to ask you to stand up for equality - for your mother, your daughter, your sister, your wife or yourself - by actively supporting the Equal Rights Amendment," Streep writes. Each packet includes a copy of "Equal Means Equal," a book by Jessica Neuwirth, president of the ERA Coalition.

Congress passed the Equal Rights Amendment in 1972. Over the next decade, 35 states ratified it, three short of the 38 needed to add it to the Constitution.

Conservative opposition and other factors halted its momentum. They have helped relegate the ERA to America's political backburners ever since. Still, lawmakers from both parties regularly try to restart the process.

The proposed amendment states, "Equality of rights under the law shall not be denied or abridged by the United States or by any State on account of sex."

Streep, who turned 66 Monday, is among numerous celebrities who say disparities between men's and women's average salaries are one reason the amendment remains relevant and needed.

"A whole new generation of women and girls are talking about equality - equal pay, equal protection from sexual assault, equal rights," Streep's letter says.

Advocates in Hollywood and Washington are battling the notion that the ERA is an artifact whose time has passed.

"The time is ripe to ratify the Equal Rights Amendment," says Rep. Jackie Speier, D-Calif. "Seventy percent of people polled think that we already have an ERA in the Constitution and they're shocked to find we don't have one."

Comedian and author Chelsea Handler says, "You wouldn't think that in 2015, in the United States, women still need to fight for legal equality, but here we are."

Link to original article from MSN Capitol Hill Buzz