The anti-gay National Organization for Marriage is urging its supporters to stop passage of the Employment Non-Discrimination Act in the group’s latest involvement in an issue outside of marriage.

In an email blast sent to supporters Friday morning, Brian Brown, NOM’s president, calls for the defeat of ENDA, saying the legislation’s prohibition on anti-LGBT job bias is a “trojan horse” that would “attack the foundational institution of marriage between a man and a woman.”

“In the wake of Justice Kennedy’s misguided opinion in the DOMA case (Windsor v. U.S.) it is certain that this federal ENDA bill will become a fulcrum used by same-sex ‘marriage’ activists to try to foist a marriage redefinition regime on the entire country,” Brown writes.

Brown insists that with ENDA in place, courts will have rationale to “easy rationale” to overturn bans on same-sex marriages when confronted with legal challenges for these laws.

Michael Cole-Schwartz, a spokesperson for the Human Rights Campaign, said the latest efforts by NOM against ENDA demonstrate its true focus isn’t marriage, but something broader.

“NOM’s opposition to ENDA is yet further proof that their mantra of ‘protecting marriage’ is nothing more than anti-LGBT animus,” Cole-Schwartz said. “They oppose any level of protections for our community and represent a small and shrinking minority of people.”

Brown contends in the email individuals who oppose same-sex marriage would be subject to lawsuits under the proposed legislation by expressing their view in the workplace.

“Under the law, individuals holding the common-sense belief that marriage is about giving kids a mom and a dad would be subject to punishment,” Brown writes. “Expressions of support for true marriage in the workplace would no longer be a fundamental right, but discriminatory, bigoted and an actionable offense!”

Tico Almeida, president of Freedom to Work, insisted the argument that opponents of same-sex marriage would be punished under ENDA isn’t true.

“NOM’s argument is absurd and shows they know they’re losing this debate on the actual issues addressed in this legislation,” Almeida said. “After ENDA, employers like Chick-fil-A’s Dan Cathy will retain the right to say or tweet anything he wants about marriage and to donate all he wants to anti-gay organizations that oppose marriage equality. ENDA’s protections against workplace harassment will adopt Title VII’s high standard for a ‘hostile work environment’ requiring abusive comments and epithets that are frequent and severe before an employee can bring a valid claim.”

Listed within the email blast are the numbers of eight Republican senators that NOM identified as potential swing votes on ENDA: Sens. John McCain (R-Ariz.), Rob Portman (R-Ohio), Orrin Hatch (R-Utah), Kelly Ayotte (R-N.J.), Jeff Flake (R-Ariz.), Dean Heller (R-Nev.), Pat Toomey (R-Pa.) and John Barrasso (R-Wyo.). Brown urges supporters to call the office of these “to make sure these senators know where the majority of Americans stand on this dangerous bill.”

The mailing is the latest involvement from NOM in an issue that is relevant to the LGBT community, has not overtly related to marriage. The organization previously joined efforts to overturn the California transgender student law, which enables transgender students in California to participate in programs and athletics consistent with their gender identity. According to Right Wing Watch, Brown has also travelled to Russia to urge passage of a law in the country prohibiting same-sex couples in other countries from adopting Russian children.