US President Barack Obama reopened a culture war battle over contraception Wednesday, saying Mitt Romney’s Republicans would take women’s preventive health care back to the 1950s.

In a direct pitch for the votes of women, who could be crucial in November’s election, Obama flew to Colorado to tout his health care law, which mandates coverage for preventive services like mammograms and contraception.

“When it comes to a woman’s right to make her own health care choices, they want to take us back to the policies more suited to the 1950s than the 21st Century,” Obama said, in a stinging attack on Republicans.

Obama argued that Romney, who has vowed to repeal the historic and controversial health care law, would wipe out several important victories in the struggle for women’s health rights.