Washington  - Residents of the US capital got one step closer to representation in Congress on Thursday.

The US Senate approved 61-37 legislation that would provide Washington with one voting member in the House of Representatives. The capital has never had a vote in Congress because it is not part of any US state and supporters say it is undemocratic to deny them representation.

Opponents argue that the measure is unconstitutional, because the Constitution only provides for representation for the states. Supporters counter that Washington could be granted a vote by Congress, which exercises broad control over the district.

Similar efforts have failed for years to gain traction. The bill approved by the Senate is part of a compromise that would also provide an additional member of Congress to Utah - in a move to maintain the body's partisan makeup with the predominantly Republican state balancing out the heavily Democratic city.

The measure must still be approved the lower House of Representatives and signed into law by President Barack Obama, who has said he supports the idea. But the idea is likely to face legal challenges and could end up before the US Supreme Court.

Residents in the city of 600,000 have only been able to vote for president since 1961. They are currently served by a non-voting delegate in the House. (dpa)