A federal judge has given the go ahead for a legal challenge to President Barack Obama’s signature piece of legislation, the controversial overhaul of the vast U.S. health care system.

Numerous lawsuits challenging the legislation have been filed since the bill passed in March.

On Thursday, Florida Northern District Senior Judge Roger Vinson ruled that a lawsuit challenging one aspect of the law – a requirement that most Americans carry some health insurance by 2014 or pay penalities – could move forward.

Last week a federal judge in Michigan upheld the constitutionality of the individual mandate in a separate lawsuit.

This legal uncertainty has analysts thinking this challenge will eventually land on the steps of the U.S. Supreme Court.

Vinson had already indicated at a hearing last month that he would reject parts of a motion by the Justice Department to dismiss the lawsuit, led by Florida and 19 other states.

The suit was originally filed in March by mostly Republic state attorneys general.

In his formal ruling on Thursday, Vinson said the case would continue as scheduled. He had previously set a hearing for December 16.

The individual mandate is one of the keys to the health care overhaul.  Without it, the law likely doesn’t work.  Prohibiting insurance companies from dropping or refusing customers or placing lifetime limits on payouts will cut deeply into profits.  To keep insurance rates down, the law requires every American to have insurance.  That means healthy, young customers are paying into the system to subsidize those who go to the doctor more often and require more health services.  Without an individual mandate, insurers lose millions of customers’ premiums from healthier Americans.