A HUGE police presence has taken to the streets of Denver, Colorado, in preparation for the start of the Democratic National Convention today as anti-war protesters pledged to disrupt proceedings as they did in Chicago in 1968.

The 1968 convention was a public relations disaster for the Democratic Party as demonstrations over the Vietnam War were met with rubber bullets and tear gas and exposed the deep divisions within the party on the issue.

A repeat seems unlikely in 2008, however, as demonstrators will be kept well away from the venue, which is heavily cordoned by kilometres of metal fencing. The surrounding streets are being patrolled by thousands of police, including Denver officers on bikes, state police on horseback and SWAT teams wearing body armour and helmets and armed with tear gas guns.

The army is also providing air cover from a helicopter that is constantly circling over the Pepsi Centre, the basketball arena that will host the four-day event, and the Secret Service is patrolling within the centre itself.

There have already been several marches by Code Pink and other anti-war groups, co-ordinated by an internet organisation, Recreate68, down the main shopping precinct of Denver. The protests halted public transport but the numbers were relatively small, ranging from hundreds to a couple of thousand in one rally - and the protesters are likely to be outnumbered by police.

The Republicans have also established a "war room" within walking distance of the Pepsi Centre. Rudy Giuliani and the former Massachusetts governor, Mitt Romney, who is the favourite to be John McCain's vice-presidential nominee, will spearhead a sequence of press conferences designed to distract attention from the goings-on up the street.

The main speeches of the Democratic convention will take place each night between 7pm and 9pm (11am to 1pm Eastern Australian time) and will provide the emotional high points of the convention.