Democrats have pledged to target seven House Republicans who switched their votes on a gay rights measure.

According to The Hill, an official for House Democrats' campaign arm (the Democratic Congressional Campaign Committee) said that the vote is expected to become a major issue in close races.

At issue was President Barack Obama's executive order protecting LGBT workers in federal contracts.

Republicans late Wednesday approved an amendment to a defense policy bill that aims to extend a “religious exemption” from the Civil Rights Act of 1964 to all government contractors.

The amendment's vague language “could be exploited as a license to discriminate against LGBT Americans by almost any federal contractor,” Rep. Richard Hanna, a Republican, told the Rules Committee on Tuesday.

Amid shouts of “Shame! Shame!” from Democrats on Thursday, seven Republicans were persuaded by GOP leaders to switch their votes after the clock ran out on an amendment to a spending bill that would uphold Obama's order. The amendment failed by one vote.

Democrats quickly shared the names of Republicans who changed their votes: Reps. Darrell Issa, Jeff Denham, David Valadao of California; Greg Walden of Oregon; Bruce Poliquin of Maine; and David Young of Iowa. Four of those lawmakers, Young, Poliquin, Denham and Valadao are believed to be the most vulnerable.

In a statement, Poliquin denied the claims: “I am outraged that political opponents or members of the press would claim or insinuate that I cast a vote due to pressure or party politics. No one controls my vote,” he said, adding that “I abhor discrimination in any form and at any place.”