She said conservatism used to be an idea. A philosophy about the proper role of government in the lives of its citizens. It has in large measure devolved into a checklist of specific issues about which there can be no disagreement without regard to the appropriateness of government's involvement in the issue.
Your mother is right. The left has successfully fragmented the electorate by special interest groups, and reduced the election to a list of special interest single issues:
Women = abortion and birth control
Unions = forced union membership
Blacks = affirmative action
“The Poor” = food stamps, entitlements
Elderly = Medicare, SS
Hispanics = immigration
All of the above = goodies from the government