Good morning from the BBC's Washington bureau. This morning the US Supreme Court is set to hand down its decision on whether President Barack Obama's signature healthcare reform is legal under the terms of the US consitution.
It is one of the biggest news days of Mr Obama's term in office, and we'll be bringing you news and commentary as the morning unfolds. Stay with us to hear from our team of correspondents, from the smartest analysts in Washington, and reaction from all sides in the healthcare debate - from politicians to ordinary Americans.
Here's a bit of background to get the ball rolling this morning: The US lacks a single-payer or tax-based healthcare system like the UK's National Health Service. Most Americans receive care through a patchwork of private insurance plans provided by employers or bought on the open market, and government-run programmes for the poor, elderly and veterans.
About 50m Americans lack health insurance altogether. Since the mid-20th Century US presidents have sought to reform the healthcare system. After a bitter and protracted battle, Mr Obama and Congressional Democrats succeeded in passing the Affordable Care Act in 2010.
The law was derided by its opponents as "Obamacare" - you'll hear that term a lot today. Its centrepiece was a requirement that Americans obtain insurance or pay a tax penalty. Whether that requirement is constitutional is at the centre of today's eagerly anticipated ruling.
The Supreme Court session opens today at 10:00 local time (14:00 GMT) at its stately building directly opposite the US Capitol here in Washington. The court is expected to announce its healthcare decision at about 10:15 local time.
0948 Jonny Dymond, BBC News, Washington
The crowd outside the Supreme Court has now swollen, the pavement is rammed with protesters and demonstrators, milling around (if they can move) and chanting. It's a great American scene.
The buzzer has sounded in the Supreme Court, signalling that the justices are set to emerge from their chambers with some decisions in hand.
Here's a handy graphic we've put together to illustrate the extent of the US healthcare insurance issue.
Source: US Census Bureau
We're hearing the healthcare decision has just come down.
News of the ruling is complex and nuanced. ScotusBlog says: "The individual mandate survives as a tax" and "The mandate is constitutional. Chief Justice Roberts joins the left of the Court". ABC News says the individual mandate is allowed.