Updated

It'll be a hot one in Missouri.

We're talking about the weather, not the turnout expected for Tuesday's primaries in the Show Me State.

Secretary of State Robin Carnahan, who is also running for the Democratic Senate nomination, projected 24% of Missouri voters would go to the polls. Some fellow-Democrats suggest mid-teens is more likely.

Add to that, the forecast calls for temperatures across the state in the high-90's, peaking over 100 degrees in St. Louis...and turnout may evaporate in the heat.

Despite that there are races of note...maybe the most interesting is an unusual August statewide referendum. The item is Proposition-C. It takes aim at a key provision of federal health care reform. If passed, Prop-C would mandate Missouri block the federal mandate that each person have or buy medical coverage.

"Never in the history of our country has government required, you have to buy a product, any product, with your own money against your will," says State Senator Jane Cunningham one of the sponsors of the legislation which ultimately became Prop-C.

Missouri will be the first of four states with some kind of public vote on the federal health care reform legislation. Polling has been sparse. What little of it suggests Prop-C will likely pass.

Then what?

Opponents (like the League of Women Voters, Job for Justice and most Democrats) scoff that Prop-C is unconstitutional. Indeed, the U.S. Constitution reads that federal law is the "supreme law of the land", superseding state law. Linda McDaniel of Missouri's League of Women Voters notes, "You really cannot pick and choose specific parts of federal legislation to abide by."

So...if you sense a possible lawsuit on the horizon, you are correct. "That's what we're counting on, says Prop-C supporter Annette Read.

Perhaps not surprisingly, the likely major party winners in Missouri's U.S. Senate race are on opposite sides of Prop-C. Robin Carnahan is against Prop-C and says she would have voted for the health care legislation. Republican Congressman Roy Blunt is in favor of the ballot issue and cast several "no" votes on health care reform.

Click here to find more of our AEHQ Days to Decide coverage.