Democratic Senator Patrick Leahy is again to attempt an amendment to the US immigration bill, which would include sponsorship for same-sex partners of US citizens, after withdrawing a similar measure earlier in the committee stage.

On Tuesday, Senator Leahy filed the amendment to the immigration bill, despite having filed, and withdrawn the amendment before, reports Politico.

After the amendment was withdrawn, the committee passed the bill 13 votes to 5.

“Seeking equal protection under our laws for the LGBT community is the right thing to do,” he said in a statement on Tuesday. “I withheld my anti-discrimination amendment during the Senate Judiciary Committee markup. As the entire Senate turns to debate the immigration bill, the fight for equality must go on.”

The amendment, which had the backing of President Barack Obama, was previously proposed by Leahy, as he attempted to convince Republicans to support it, however some on the fragile bipartisan coalition said they would vote against the bill if the amendment was included.

Advocates of adding gay couples to the key bill, estimate that around 36,000 couples already live in the US who are not able to obtain the necessary green card, with more living abroad because they cannot obtain the visa.

Back in February, Democratic Senator Patrick Leahy also proposed a separate bill which would allow US citizens to sponsor their same-sex partners for residency visas, however advocates recognised that the bill was unlikely to pass in the Republican controlled US House on its own, rather than being included in the larger, more comprehensive bill.

It is currently unclear whether Leahy’s new amendment will get a vote, as Republican majority and Democratic minority leaders in the Senate are still reaching an agreement on amendments.

The amendment would need at least 60 votes in order to pass.

As well as the immigration bill, the Supreme Court could also weigh in on the issue, as it is expected to rule by the end of June on the case around the Defense of Marriage Act (DOMA), which could see same-sex partners applying for green cards.