Ten states hold Democrat primary polls on 2 March, including California, New York, Ohio and Georgia.
The states offer up more than half the 2162 delegates required to secure the party’s nomination for presidential candidate at the Democratic national convention in July.
The Massachusetts senator is leading in opinion polls across all ten states and a clean sweep on so-called Super Tuesday will effectively confirm the decorated Vietnam veteran as the Democrat challenger to President George Bush.
But Kerry’s second-placed rival, North Carolina senator John Edwards, aims to keep his challenge alive by winning at least one state.
Meanwhile, Reverend Al Sharpton and Ohio Congressman Dennis Kucinich, both progressive leftist liberals, hope sustaining their long-shot campaigns will at least influence the agenda of the two front runners.
The biggest prize on Super Tuesday is California, a relatively liberal, prosperous state that sends 370 delegates - one sixth of the national total - to the Democratic national convention.
Kerry seems poised for a sizeable win, not because voters find him far more appealing than his rivals, but because having pocketed 18 state victories out of 19 already, he enjoys the perception of electability.
"In general, voters want to back a candidate who can win," said Frank Newport, editor-in-chief of pollsters Gallup in Princeton, New Jersey.
"In general, voters want to back a candidate who can win"
Newport said Kerry’s earlier victories had created a "momentum factor" that gave him an advantage over his rivals.
But Edwards hopes for a late surge here and in New York, plus a surprise victory in Ohio - an industrial state where the miller’s son has campaigned hard for the working class vote.
He also hopes to win in Georgia, part of the southern belt that the North Carolina senator says he best represents.
With two more big southern states - Florida and Texas - set to vote on 9 March, Edwards’s campaign will not die if he fails to impress on Super Tuesday.
But it will at least be admitted into intensive care, with added pressure on him to step aside so that Kerry can lead a unified assault against Bush.
Practically speaking, said Newport, if Kerry won most of Tuesday’s delegates, Edwards might find it impossible to catch up.
In a televised debate on Sunday, Edwards signalled a change in tactics that have so far earned him only one state primary victory - in his birthplace of South Carolina.
Having campaigned as the one candidate who did not attack his rivals and traded on his "likeability", the affable Edwards strained to distinguish himself from Kerry, a veteran of national politics for 19 years.
"This is the same old Washington talk that people have been listening to for decades," said Edwards after one Kerry answer.
Lawyer John Edwards is fighting
to keep his campaign alive
Edwards, a millionaire personal injury lawyer, has held his senate seat - his first national post - for five years.
The sniping clearly irritated Kerry, who stressed his "experience and proven ability" and suggested his main rival "should do his homework".
The other two main candidates, Sharpton and Kucinich, have fought for attention.
Sharpton, an outspoken civil rights campaigner, complained the questioners were ignoring him, dismissed Kerry’s liberal credentials and suggested Edwards’s sole primary victory did not justify the attention the southern senator enjoyed.
And Kucinich, buoyed by his second place showing in the Hawaii primary last week, noted he was the only candidate who had voted against the Iraq war resolution.