Franklin Delano Roosevelt was inaugurated on 4 March 1933. "This nation asks for action", he said in his inaugural address, and he answered the call. By the time Congress adjourned on 15 June, he had sent it fifteen messages and persuaded it to pass fifteen major pieces of legislation. And they were major. They included the Banking Act and the Glass-Steagall Act, separating commercial and investment banking; the Agricultural Adjustment Act to establish a policy to save American farming; and the National Industrial Recovery Act to do the same for industry. He set up the Tennessee Valley Authority and sponsored an international financial conference, passed numerous reforms of the mortgage industry and took the United States off the gold standard.

These were the famous "hundred days", in the course of which Roosevelt saved American capitalism and - some would say - saved American democracy as well. The period set a standard by which the wisdom and effectiveness of future presidents was to be judged.

In 1961, media judgment of the achievements of John F Kennedy's first hundred days in office was harsh (and the president was no less self-critical). He had been far from inactive. But his successes were seen as having been cancelled out by the catastrophic failure of his attempt to overthrow Fidel Castro's regime in Cuba. Kennedy, asked how he liked being president, answered wryly that he had liked it better before the Bay of Pigs.

Even JFK's humiliation could not compare with the original hundred days, which measured the interval between Napoleon's escape from exile on the island of Elba and his decisive defeat at Waterloo.

Barack Obama approaches the end of his first hundred days in office with a record that lies somewhere between those of Roosevelt and Napoleon. He has been as active as FDR; avoided any disasters; and has certainly not met his Waterloo. This is, then, a good moment to assess how he has performed so far in terms of what he wants to achieve, and what his supporters expect from him.

In the world's eye

For President Obama to do better than his predecessor internationally was always going to be easy. For George W Bush was disliked by huge numbers of the world's people, and an even larger proportion of their leaders; indeed, the degree of loathing exceeded that visited on almost any other American president.

But Obama has not just basked in the widespread relief at his arrival in the White House; he has also acted well. He said on his first day in office that he would close the Guantánamo prison camp, and is working on it; within a few more days he had struck the note the world wanted to hear on Iraq, on torture and on climate change.

His meetings in Europe and Turkey for a series of summits on 2-7 April 2009, and in Trinidad & Tobago for the Summit of the Americas on 17-19 April, were an almost unqualified success. People everywhere liked and trusted him. (The one partial exception was his urging the European Union to accept Turkey as a member: the reaction in Washington if France's Nicolas Sarkozy were to urge the United States to accept Mexico as the fifty-first state!)

Only gradually has it emerged that while Obama may understand the world's anger at the Bush administration's hubris and rudeness, his own foreign policy in many ways is set to continue the established themes of American policy. He might be ready to draw down US forces in Iraq; but only to send more to Afghanistan. He might have appointed excellent regional special envoys - Richard Holbrooke, George Mitchell, Dennis Ross; but with no expectation of dramatic progress in their areas of responsibility.

Obama's public demeanour may be hugely welcomed across the world. But the US under his leadership will still pursue many of America's great-power goals. The fist might open into a handshake, but his remains a project for a new - if less aggressive - American century.

In the domestic arena

At home, as the hundred days end on 29 April 2009, President Obama's record is even more ambiguous. No one doubts his determination to drag the American economy out of the quagmire. Many doubt whether his administration (studded as it is on the financial side with those most associated with the policies that caused the trouble in the first place) knows how to do the job.

Equally, no one doubts the sincerity of his reform agenda. But many doubt whether, given the slowdown of the economy and the ballooning of the budget deficit, he will be able to advance his social and environmental goals: introducing universal healthcare insurance, investing on a significant scale in public education, and reducing America's dependence on imported energy.

Only a fool, said JP Morgan, would "go a bear" on the United States. But a very large number of fools did "go a bull" on a scale that has come close to ruining the world's strongest single economy (and thus, in a globalised economy, to ruining everyone else's). 

Indeed, what President Obama's first hundred days illustrate is the limited ability of the American presidency to respond to the country's real needs. The glamour, the excitement and the appeal of the US presidency were graphically on view at the inauguration on 20 January - but almost immediately the limitations of presidential power were apparent.

This is highlighted by the fact that key offices in the treasury remained unfilled for weeks at the height of the worst financial crisis since the early 1930s - because a constitutional provision requires high offices to be subject to the advice and consent of the Senate, ensuring a slow process at the best of times.

It is also clear in the president's difficult relationship with Congress. The legislative process in the House of Representatives (which controls money bills) is encrusted with the new system of "earmarks" and other special interests that tread close to the borders of corruption. In the Senate, an administration's need (thanks to comparatively new conventions) to in effect win three-fifths of the votes to pass legislation makes the process lengthier. In both chambers, the committee system - cumbersome and exposed to special-interest lobbying - is now closer than ever to paralysis. 

The problems are compounded by the fact that among the many high-minded people in Congress, there are few towering figures. In part, this is because the public sees the political system as dominated by presidential will and presidential action - an illusion that the media (and especially) television has reinforced. The president is portrayed as dynamic, the Congress and other institutional rivals as bumbling. The use of phrases such as "commander-in-chief" and "leader of the free world" for the president, contrasted with the supposed parochialism and self-interest of senators and congressmen, further exaggerates the contrast.  

In the balance

Already, as the hundred days come to an end, older political realities have reasserted itself. The forces of inertia look heavier than ever. The Obama administration acted with decisiveness and energy to recapitalise the banks. The bankers simply took this as an opportunity to strengthen their balance-sheets and keep paying themselves bonuses. The country's manufacturing industry is in such a poor shape that Fiat is seen as a potential saviour for both Chrysler and General Motors. The faint signs of revival on Wall Street contrast with the bleak outlook on Main Street, where real-estate values continue to fall and unemployment continues to rise (see "Barack Obama: end of the beginning", 30 March 2009).

When I travelled across the United States at the time of the inauguration to discuss The Myth of American Exceptionalism [Yale University Press, 2009] - a book that is very critical of aspects of American democracy - I was constantly asked how I could say such things when America had just elected Barack Obama. My reply was two-fold: that the double task of reforming the inequalities and the inefficiencies of American society while rescuing an imploded financial system seemed almost beyond the strength even of the strongest president; and that in any case the presidency did not now have the powers or the influence it would need to complete this task.

The presidency, after all, was far from all-powerful even in Franklin Roosevelt's day. FDR complained that getting the Washington government, and especially the US navy, to do what the president wanted was like punching a pillow. In All Things to All Men: The False Promise of the Modern America Presidency (1980), I showed in detail how Roosevelt had responded to challenges as frightening as those confronting Barack Obama by using a range of instruments - the Congress, the Democratic Party, the permanent government, and the press and radio - to lessen his isolation within the constitutional system. "By the end of his twelve years in the White House", I wrote, "the temporary shift in the balance of power between the President and the Congress resulting from then dramatic initiatives of the Hundred Days had become the way Washington worked."

"For all that", I went on, "he had done nothing to change the rules of the game. He had simply shown how it was possible to win most of the time. In so doing, he had greatly heightened expectations - both in Congress and in the nation - of what his successors would be able to accomplish". FDR's presidential domination is not the way Washington works today.

The fact that Roosevelt was president during a period of unprecedented crisis at home and abroad may have strengthened his authority as well as testing it, yet this still did not permit a permanent change. The six decades since Roosevelt's death have seen all of his successors, several of them men of great force of character and formidable political skill, fail to make the system work as well as he did.

Harry Truman, working with the presidency as Roosevelt had left it to him, did as well as anyone. Dwight D Eisenhower did better, as historians now recognise, than his liberal critics thought at the time. Both John Kennedy and Lyndon B Johnson, activist Democratic presidents, complained vociferously of their powerlessness and railed against the constraints of the system.

After them, the president's situation became even harder. Richard M Nixon was driven from office amid scandal. Gerald Ford and Jimmy Carter were derided, then defeated. Ronald Reagan came to the White House announcing that government was the problem, not the solution, a belief that did nothing to make government more effective. George HW Bush was an excellent foreign-policy president, but unsuccessful at home and defeated in a re-election bid. Bill Clinton only narrowly avoided ejection and George W Bush became a model of unpopularity.

If the American president has (as the textbooks say) to perform the roles both of an elected monarch and a consecrated prime minister, the record of the past two generations suggests that the monarchical attributes of the office have fared better than its administrative and political fortunes.

Barack Obama has in his first three months confirmed his possession of formidable political skills. The question must be whether they will be enough to help him transcend the very real constraints and weaknesses of what is constantly, but inaccurately, described as the most powerful office in the world.