Missouri voters on Tuesday overwhelmingly rejected a federal mandate to purchase health insurance, rebuking President Barack Obama's administration and giving Republicans their first political victory in a national campaign to overturn the controversial healthcare law passed by Congress in March. "The citizens of the Show-Me State don't want Washington involved in their health care decisions," said Sen. Jane Cunningham, R-Chesterfield, one of the sponsors of the legislation that put Proposition C on the August ballot. She credited a grass-roots campaign involving Tea Party and patriot groups with building support for the anti-Washington proposition. With most of the vote counted, Proposition C was winning by a ratio of nearly 3 to 1. The measure, which seeks to exempt Missouri from the insurance mandate in the new healthcare law, includes a provision that would change how insurance companies that go out of business in Missouri liquidate their assets.