The Supreme Court on Monday joins the nation's vitriolic debate over the landmark health-care law and the limits of federal power. And though thousands of pages of legal arguments about the Constitution's history and the court's precedents have landed on justices' desks, the outcome may also hinge on less tangible factors.

Public opinion. The nation's volatile political climate. The court's self-consciousness about its own partisan divide. And the pivotal role it plays in deciding the nation's thorniest social issues.

Experts say all of those go into the mix as justices consider the extraordinary step of striking down -- for the first time since the New Deal -- a monumental domestic program proposed by the president and passed by Congress.

The three days of arguments that begin Monday are the inevitable result of a legal battle that began the moment the Patient Protection and Affordable Care Act became law two years ago. And the court's conclusion will land in the summer heat of a presidential campaign in which each of President Obama's Republican challengers have made opposition to the law an unshakable pledge.