Why are we asking this now?
Mr Obama has said he wants a final up-or-down vote on a measure to reshape US healthcare, a goal which has defeated every American president since Harry Truman, and with the approach of November's mid-term elections, the stakes grow higher by the day. Healthcare reform has turned into an acid test for the country's entire political system. As Mr Obama put it this week: "At stake right now is not just our ability to solve this problem, but our ability to solve any problem."
Shouldn't this have been wrapped up long ago?
Indeed. Since last May, healthcare has dominated the legislative agenda to the exclusion of virtually all else. Despite the bill's complexity, problems with various Democrats and blanket opposition from Republicans, it almost reached the finish line when the Senate passed its version in December, when Democrats still had the 60 votes to overcome a Republican filibuster.
But just when things seemed set fair, that 60th vote needed for passage of a final bill combining the House and Senate versions vanished when Republican Scott Brown won the Massachusetts seat of the late Ted Kennedy – by bitter chance the Democrat most identified with health reform. Obama had hoped to sign a final bill by the time of his State of the Union address on 27 January. Now the effective deadline is the Congressional Easter recess, which starts on 28 March.
Is Mr Obama himself partly to blame?
In retrospect, probably yes. Having made healthcare his signature issue, he failed to crack the whip with Congress, mistakenly assuming that with their large majorities in both House and Senate, Democratic leaders on Capitol Hill could see the project through. The White House underestimated both the ferocity of his Republican opponents and divisions among Democrats. Others say he should have focused on the economy and jobs, the biggest concern of voters, rather than healthcare. Some have likened his obsession with the latter to Captain Ahab's self-destroying pursuit of the great white whale in Herman Melville's novel Moby Dick.
Is he offering 11th-hour concessions to Republicans?
It depends how you look at it. Last week's televised bipartisan "summit" organised by the White House was just a gimmick, primarily designed to show the country that the Republicans were opposed to compromise of any kind. This week, he offered to incorporate some Republican ideas, notably on cutting fraud, and expanding so-called "health savings accounts". But such changes would be pretty marginal. In any case, Republicans have rejected them as nothing more than a gambit by Democrats to win political cover for a measure that according to the polls, a majority of Americans now oppose.
Why are the Republicans so unyielding?
To paraphrase Harold Macmillan, "politics, dear boy, politics" – and in the US politics is an especially brutal, bare-knuckle sport. Republicans are sure healthcare reform will be a "heads-I-win, tails-you-lose" issue at the mid-term elections, at which they could conceivably regain control of both Senate and House. Support for it, they calculate, could be fatal for Democrats in November.
By presenting "Obamacare" as a government takeover of a sector that accounts for a sixth of the entire US economy, they can tap into Americans' ancestral suspicion of government, and depict the President as that most dreadful of creatures, a "Socialist". But it's worth remembering that epic US political battles are often fought over changes that in retrospect seem blindingly obvious. Civil rights is one example; another was the 1965 Medicare and Medicaid legislation, creating federal health care programmes for the elderly and the poor, but branded at the time by Republicans as virtual communism. Now Medicare is all but sacrosanct.
What are the stakes?
Enormous. If healthcare reform goes down in flames, Obama's authority and prestige will take a colossal hit, among the general public and his own Democrats. He will be perceived as weak. Republicans will be emboldened to block other key initiatives like financial market regulation and climate change legislation.
A sense that the country is ungovernable will only grow. But if Obama can force a bill through, he will prove that this calm and cerebral president can also get things done – to whit, the biggest single overhaul of healthcare since the 1960s. Right now everything is in the balance. No wonder that, try as he might to kick the habit, Obama still needs the odd cigarette.
How can Democrats pass a healthcare bill without that 60th Senate vote?
By a process called "reconcilation" that requires a simple majority in the Senate to pass, if necessary with Vice-President Joe Biden's deciding vote to break a 50-50 tie. Reconciliation can be used for budget-related bills that reduce the deficit. In this case, the House first passes the Senate bill as it stands. Then the House passes a reconciliation package of agreed changes that have an impact on federal spending. That measure is sent to the Senate which passes it with the up-or-down vote Obama is demanding.
But is reconciliation bomb-proof?
As Congress currently works, nothing is bomb-proof. In November, the House only passed its health bill by 220-215, a majority of five, and one of the 220 is dead and another has switched sides. Liberal supporters who had misgivings about the original House measure will have to hold their noses even tighter if they are to accept the more conservative Senate version unchanged.
Divisions on abortion (specifically, on whether it should be absolutely barred from coverage in a reformed healthcare system) are also re-emerging in Democratic ranks. In the Senate, Republicans can use other devices to tie up proceedings for the next week or two, even without recourse to a filibuster. And whatever happens, the mere use of reconciliation would make the political atmosphere even more toxic than it is now.
If the bill passes, will it really be a new dawn for healthcare in the US?
Proponents of a single-payer system, or a European version of universal healthcare, will be disappointed. But reform would extend coverage to two-thirds of the estimated 45 million Americans without it. It would also impose strict new rules on the insurance industry, barring them from refusing coverage to people with pre-existing medical conditions. Its cost of almost $1 trillion, it is claimed, will be covered by tax increases on some existing plans and other economies. By American standards it would be a huge advance. And one thing is certain. If nothing is done, the US will face an even bigger healthcare crisis in a few years' time.
Will Obama get healthcare reform?
* The Democrats still have 59 Senate votes – not 60, admittedly, but comfortably more than 51
* House rules allow the Speaker Nancy Pelosi great leeway to muscle legislation through
* The stakes are now so high that Democrats simply dare not let Obama fail
* Too many Democrats are scared of losing their seats in November if they say yes now
* Republicans will find new procedural devices to make passage in the Senate impossible
* Democratic divisions in the House, especially on abortion, will cause the bill to fail