Republicans are bracing for a battle where substantive arguments could be swamped by political optics and the intensity of the clash over women’s issues. At a closed-door Senate Republican lunch on Tuesday, Senator Lisa Murkowski of Alaska sternly warned her colleagues that the party was at risk of being successfully painted as antiwoman — with potentially grievous political consequences in the fall, several Republican senators said Wednesday.

Some conservatives are feeling trapped.

“I favor the Violence Against Women Act and have supported it at various points over the years, but there are matters put on that bill that almost seem to invite opposition,” said Senator Jeff Sessions, Republican of Alabama, who opposed the latest version last month in the Judiciary Committee. “You think that’s possible? You think they might have put things in there we couldn’t support that maybe then they could accuse you of not being supportive of fighting violence against women?”

The legislation would continue existing grant programs to local law enforcement and battered women shelters, but would expand efforts to reach Indian tribes and rural areas. It would increase the availability of free legal assistance to victims of domestic violence, extend the definition of violence against women to include stalking, and provide training for civil and criminal court personnel to deal with families with a history of violence. It would also allow more battered illegal immigrants to claim temporary visas, and would include same-sex couples in programs for domestic violence.

Republicans say the measure, under the cloak of battered women, unnecessarily expands immigration avenues by creating new definitions for immigrant victims to claim battery. More important, they say, it fails to put in safeguards to ensure that domestic violence grants are being well spent. It also dilutes the focus on domestic violence by expanding protections to new groups, like same-sex couples, they say.

Critics of the legislation acknowledged that the name alone presents a challenge if they intend to oppose it over some of its specific provisions.