[Rupert Cornwell has written articles published in The Independent.]

Young Malia Obama at least is not getting carried away. "First African American president – it better be good," was the 10-year-old's wise comment about the address her father will deliver immediately after being sworn in to office at noon today. She picked the right spot too, during a family visit last week to the Lincoln Memorial, at the opposite end of the Washington Mall from the Capitol where Barack Obama will speak.

Abraham Lincoln is the patron saint of this inauguration, like Obama a man from Illinois, the president who liberated the slaves to whose race the soon-to-be 44th president belongs. But the setting for Malia's remark was as least as intimidating as it was inspirational. Engraved on the Memorial's inner wall, alongside the brooding statue of the great man, is his second inaugural address – 703 words long – and the gold standard against which the addresses of every President are now judged, and invariably found wanting. But if ever America needed one to match it, is is now.

This is surely the most keenly awaited inaugural speech in modern US history, perhaps ever. It will be delivered by a man renowned for his exceptional eloquence, at a moment when not just America but the world is looking for a giant pick-me-up, in the depths of the biggest economic crisis in 80 years. Its global audience probably will run into the billions, hanging on its every word.

Oddly, it is nowhere written in the constitution that an incoming president must make such a speech. But in 1789, after he became the first president to be sworn into office, George Washington decided he'd better deliver one anyway – and like most things decided by Washington it became a precedent set in stone.

In fact, those early inaugurals were above all designed to be read. They would set out the beliefs and broad political intentions of a president, and his generally ponderous reflections on the age. Only when it could not be avoided – such as with Lincoln's addresses, both overshadowed by the Civil War – did they address specific issues in detail. To this day, most of them haven't been very good, and almost none have changed history. However irrationally, this time people are expecting both from Barack Obama...