LGBT rights activists gathered outside the office of a US Senator on Wenesday, in order to protest against the decision to withdraw an amendment to a broad immigration bill, which would have protected binational same-sex couples.

The amendment, which had the backing of President Barack Obama, was proposed by Democratic Senator Patrick Leahy on Tuesday evening, 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.

The amendment also lost the backing of some Democratic members, who said they could not support it if it meant the downfall of the bill.

After the amendment was withdrawn, the committee passed the bill 13 votes to 5.

The group of around 30 protesters gathered outside Senator Marco Rubio’s Doral office. Echoing previous messages, Senator Rubio’s spokesman said: “Senator Rubio and others have noted the reality here… Approving this immigration reform legislation into law will be difficult enough as it is and, if this measure is adopted, it will virtually guarantee that the bill won’t pass and that the coalition that helped put it together will fall apart.”

Last month lawmakers had expressed fears that including same-sex couples in the groundbreaking legislation could throw the bill, which is being pushed forward by a bipartisan effort, off course.

Currently, straight couples can sponsor their foreign-born spouses to obtain green cards, however there is no equivalent option for binational same-sex couples.

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.