A bill that would outlaw workplace discrimination based on sexual orientation and gender identity (transgender protections) was reintroduced in the Senate on Thursday.

The Employment Non-Discrimination Act (ENDA) was introduced by Democratic Senators Jeff Merkley of Oregon and Tom Harkin of Iowa and Republican Senators Mark Kirk of Illinois and Susan Collins of Maine.

“The right to work hard and earn a living is a fundamental right. It is essential to the success of a family. It is essential to the pursuit of happiness. It is part of equality under the law,” Merkley said.

Last year, as a member of the House, Kirk angered gay rights activists when he voted against repeal of “Don't Ask, Don't Tell,” the 1993 law that forbids gay and bisexual troops from serving openly. After winning his Senate seat, however, Kirk reversed his position, and voted to end the law.

Kirk said, “nothing provides more dignity than a job.”

“We will have more jobs and higher incomes when the most qualified individuals are given the best opportunities, regardless of orientation,” Kirk added. “This legislation ensures that.”

Openly gay Massachusetts Congressman Barney Frank reintroduced the bill in the House last week. However, nearly half of the of the bill's support from last year had eroded in the new Republican-dominated Congress.