Low-paid government contract workers rallied Wednesday outside the White House as part of a one-day strike for better pay.

“We cannot stand by and do nothing while the income of the average middle-class family has gone down by more than $5,000 since 1999,” Sen. Bernie Sanders said.

The biggest employer of low-wage workers in America is not Wal-Mart, not McDonald's, but the United States government, Rep. Keith Ellison said.

Sanders and Ellison organized letters to President Obama urging him to set a minimum-wage preference for private companies doing business with the federal government. They urged Obama to issue an executive order that would be tantamount to setting a minimum wage for federal contractors. In the senators’ letter to Obama, they suggest that at least $10.10 an hour should be paid to the lowest-paid of the some 2 million employees of private businesses that last year alone received more than $446 billion in federal contracts. 

A National Employment Law Project survey found that more than seven out of 10 workers who make military uniforms, drive trucks, serve food and perform janitorial services were paid less than $10 an hour. 

“That is simply unacceptable,” the senators wrote to the president. “Profitable corporations that receive lucrative contracts from the federal government should pay all of their workers a decent wage,” according to the letter from Sanders and Sens. Barbara Boxer (D-Calif.), Jeff Merkley (D-Ore.), Chris Murphy (D-Conn.), Brian Schatz (D-Hawaii), Elizabeth Warren (D-Mass.), Mazie Hirono (D-Hawaii), Kirsten Gillibrand (D-N.Y.), Patrick Leahy (D-Vt.), Edward Markey (D-Mass.), Jack Reed (D-R.I.), Martin Heinrich (D-N.M.), Ben Cardin (D-Md.), Sheldon Whitehouse (D-R.I.) and Tammy Baldwin (D-Wis.).

Legislation has been introduced in the Senate that would raise the minimum wage for all workers to $10.10 an hour, but it has been blocked by Republicans. Some, like the ranking Republican on the Senate labor committee, not only oppose raising the minimum but want to abolish it. The president could set the minimum wage for government contractors without action by Congress.

The senators likened an executive order on wages to a presidential directive issued in 1965 by President Lyndon Johnson prohibiting racial discrimination by federal contractors.  “It is now time to prohibit these same federal contractors from paying poverty level wages.  A job should lift workers out of poverty, not keep them in it,” the senators concluded.