If Senate Majority Leader Harry Reid wants to get the 60 votes he will need to break a Republican filibuster and pass a health care reform bill, he’s going to have to include a robust public insurance option.

Without that basic protection for consumers and taxpayers, Reid will lose the vote of Vermont Independent Bernie Sanders, who caucuses with the Democrats but has made no secret of his frustration with attempts to dumb down reform.

“I strongly suspect that there are number of senators, including myself, who would not support final passage without a strong public option,” says Sanders, who supports development of a single-payer “Medicare for All” system but has indicated he would accept a milder reform if it controls against insurance-industry profiteering.

“The American people want a public option that would compete against the private insurance companies, whose only goal in life is to make as much money as possible,” says Sanders. “If we do nothing, the dollars we spend on health care will nearly double in the next eight years.”

Sanders has not gotten as much attention as conservative Democrats who have grumbled about Congress doing “too much.”

But the Vermonter’s objection highlights that danger of doing too little.

Sanders is positioning himself as a leader in the fight for real reform.

“It is my intention to do everything I can to see that a strong bill is passed which provides universal coverage in a cost-effective way,” he says, while admitting that: “This is going to be a very difficult, complicated and contentious process which I hope and believe will, in the final analysis, succeed.”

What’s the key to success? Getting President Obama and his administration engaged in the fight for a strong public option.

“We need them in there with guns blazing,” says Sanders. “This country faces a major health care crisis. With 46 million Americans uninsured, 45,000 dying each year because they don’t get to a doctor when they should, almost 1 million going bankrupt because of medically-related bills and health costs scheduled to double within eight years, it is imperative that we pass strong health care legislation that will address these issues.”

Sanders is tight about the need for Obama to get more actively and aggressively involved.

But there is also a need for progressive senators, who back the public option, to join Sanders in signaling that they will object to a dumbed-down “reform” bill.

That’s not a threat.

It’s a way to help the majority leader keep his promise to deliver health care for all while controlling costs.

When progressives make their demands clear, Reid will have far more leverage to push for real reform.