A second Republican in the Illinois House has announced his support for a bill to legalise equal marriage, and has said that he thinks others will follow.

Representative Ed Sullivan Jr, joined Representative Ron Sandack to become the second Republican in the state to support the bill. He is also chairman of the House Republican campaign organisation.

Supporters of the bill, which narrowly passed the House Executive Committee back in February, have said they are coming close to having the 60 votes necessary for the bill to pass.

Sullivan said he thought that more of the 47 Illinois House Republicans would vote in favour of the measure to legalise same-sex marriage in the state.

“There is tremendous momentum leading up to this vote. I think we’re very close,” Sullivan said. “There’s many of my colleagues that have talked about this, that have said it’s the right thing to do.”

Sullivan, appointed in 2003, also went on to note personal reasons for his support for equal marriage, as his mother-in-law is gay.

“The first reaction from people might be, ‘Well he might be voting for that just because of his mother-in-law,’” he said. “The reality is, because my mother-in-law is gay, I have more of an understanding and familiarity with same-sex couples.”

He also went to say that he thought his pro-equal marriage stance reflected the views of his constituents.

“I try to err on the side of being a public servant and serving my district as opposed to potentially being a politician and just serving that subset (opposed based on religion) and those within my party who don’t necessarily want this to pass,” he said. “I look at this as a freedom, as a conservative view of treating people equally.”

A recent Ipsos poll of Illinois residents has found that half of people living in the state supported a bill to legalise equal marriage, with the percentage in opposition to it much lower.

On Valentine’s Day the Illinois Senate, which is controlled by the Democrats, voted 34-21 to approve the bill to legalise same-sex marriage.