by Lesley Russell

Last month United States President Barack Obama signed his landmark health care overhaul into law, saying that it provides ''the core principle that everybody should have some basic security when it comes to their health care.'' ''Today we are affirming that essential truth, a truth every generation is called to rediscover for itself, that we are not a nation that scales back its aspirations,'' Obama said.

However there is a monumental task ahead to simultaneously implement the provisions of the law and to fight back the attempts from the right to undo it. Republicans have already introduced legislation into the Congress to repeal the law. Many Republicans have said that repealing the law should be part of the Party's campaign platform for this year's midterm elections, a view fostered by the conservative media. ''Repeal and replace will be the slogan for the fall,'' Senate Minority Leader Mitch McConnell has stated. More political grandstanding has come from Republican states.

More than a dozen Republican state attorneys general have filed federal lawsuits against the new law, arguing that certain provisions violate the Constitution. Obama has invited Republicans to ''go for it'', knowing that Republicans in Congress are unlikely to succeed in repealing the law and that the lawsuits filed by the states' attorneys general have little legal backing. In their lawsuits the attorneys general claim that the requirement in the new law that all Americans purchase health insurance represents an unprecedented encroachment on the liberty of individuals and violates several parts of the Constitution.

Most legal scholars regard this claim as weak, even frivolous. It fails to recognise, for example, that president George Washington signed the Second Militia Act of 1792, which required a significant percentage of the US civilian population to purchase at their own expense ''a good musket or firelock, a sufficient bayonet and belt, two spare flints, and a knapsack'' in case the president ever called them to serve. Outside the more constrained bounds of government, things have turned quite nasty, to a level that Republican leaders have called unacceptable and un-American.

Some House Democrats have sought increased protection from Capitol Police in response to incidents of vandalism and death threats against them, their families and their staffs. The first and one of the hardest tests of the Democrats' ambitious plan to overhaul the nation's health care system lies in the law's requirement that in the next 90 days the administration must establish a federally funded insurance program to cover people turned down by private insurers because they have a pre-existing medical condition. It will last until 2014 when health insurance exchanges, marketplaces where companies compete for business, are scheduled to be up and running.

This effort to provide immediate relief to people who have no insurance options will be closely watched as an early gauge of the Obama administration's ability to turn a complex new health care law into a smooth-running program. While 34 states currently operate such programs, called high-risk pools, some are closed to new entrants and most struggle to finance coverage for approximately 200,000 enrollees nationwide. People using these pools tend to be sicker and older than the general population, and to qualify they must have been unable to obtain health insurance through other sources.

Analysts predict that nationwide about two million people might be eligible for health cover through this mechanism. The legislative language provides only the bare outlines of how such a pool (or pools) might operate, complicating a daunting timetable for implementation. Amid all the elation around this achievement, the hype about what it will mean for every American, the anger from those opposed, and the push from the bureaucrats to get it implemented, there remains the very remarkable ability and extraordinary persistence that Obama brought to the task of making this election commitment a reality.

Three years ago, as an untested and unseasoned presidential candidate, Obama made a promise that turned out to be more than just campaign rhetoric. ''I want to be held accountable for getting it done,'' he said. 'I will judge my first term as president based on the fact on whether we have delivered the kind of health care that every American deserves and that our system can afford.''

Dr Russell is the Menzies Foundation Fellow at the Menzies Centre for Health Policy, University of Sydney/Australian National University and a Research Associate at the US Studies Centre, University of Sydney. She is currently a Visiting Fellow at the Center for American Progress in Washington DC.