Chicago's Mayor Richard Daley has bitterly declared that he will brook no trouble from would-be demonstrators when the Democratic Convention gets underway in August. "I think the great mass of American people has had enough of those who carry Viet Cong flags in the streets of this country, and are getting fed up with the cry of police brutality," he told his wildly applauding City Council.

"No one is going to take over the city," stormed Daley. "They won't take over the convention or any street. If it is necessary to put on 5,000 more policemen, I'll ask for authority." He may have to.

Dissident Democrats and other angry opponents of the war, of course, have been talking of marching on the barn-like International Amphitheater much as they marched on the Pentagon last October. The prospect already has police mapping contingency plans.

From a policeman's point of view, the situation could hardly be worse. The decaying Amphitheater will be hard enough for delegates to get to without the harrassment of demonstrators. If protestors want to make things uncomfortable, the police will be hard pressed to stop them.

There are no hotels and few places to eat in the area, and delegates will have to commute from the Loop via a single expressway or the back streets of the ghetto. The city's mammoth lakefront exhibition hall--closer to downtown, isolated from residential ears, and far easier to defend--was gutted by fire a year ago, but Daley's clout and assurance of peace brought the party to Chicago anyway.

If there are demonstrations outside the hall, the neighbors are not going to like it. Though the Amphitheater is ringed by the bleak slums of the South Side ghetto, the immediate area is heavily white and largely Irish. Daley himself lives not too far away. Should Negroes march in, things could get ugly. Civil rights demonstrators have marched on the mayor's house many times, and they have, on occasion, been met with bricks and bottles.

Negroes' reaction to the convention is at this point far from certain. Chicago could be in for a massive explosion. There is, in at least one store window less than a mile from the convention hall, a dusty sign reading "Soul Brother," left over from a previous flare-up. Even the chill of winter has not been enough to discourage Negro youths from a recent rampage through a South Side neighborhood.

Events are now shaping up that could very much intensify an explosion, inflaming Negroes and spurring them to action. But these same developments could, if the Democrats are shrewd enough, divide the dissidents and put them at odds with a large segment of Chicago's Negro community.

The key is Mississippi. Negroes from the Magnolia State are going to flock to Chicago this summer in a replay of the 1964 Atlantic City attempt to unseat the party regulars. That year the party handed Negroes a compromise, seating of two of the challengers as guests; this time, a compromise will be more difficult.

There is, above all, a massive wellspring of sympathy in Chicago's ghetto for Mississippi civil rights activity. Most of the city's nearly one million Negroes have roots in Mississippi. "Chicago, Chicago, that's all you ever hear around here," says an ex-plantation worker in Greenville, Miss. Negroes in the Delta speak not of going North but of going to Chicago; and for Negroes in Chicago, going home means a visit to Mississippi.

If the Negroes challengers from Mississippi are forced to sit outside the convention hall as they were in Atlantic City, they are sure to be joined by throngs of irate supporters and by every black power firebrand in town.

But if this year's challenge is potentially more explosive, it is not nearly as simple as 1964's. In fact, the political complexities may pose as much of a problem for the anti-Johnson forces as for Johnson himself.

Delegations from two states--Mississippi and Alabama--are likely to be challenged. Party regulars in both states should have little difficulty in complying with the broad civil rights guidelines set down by the Democratic National Committee. The guides say only that party elections--as for county convention delegates--must be open to Negroes; they do not say that the national convention delegations must actually be integrated.

Even in Mississippi, with 42 per cent of the population Negro and a dozen counties capable of electing Negro officials, fair elections would not necessarily result in any Negroes on the delegation. It is selected by a statewide convention whose delegates are in turn chosen at the county level. Negroes could not possibly gain a majority of the state's 82 counties.

But neither Alabama's nor Mississippi's delegation is likely to submit to one national party dictum--a pledge to support the party's nominee. In Alabama, Johnson supporters have had to charter a new party in order to assure that the President's name--they have no doubt he will be re-nominated--will be on the ballot. The regular party will support former Gov. George Wallace.

In Mississippi, Gov. John Bell Williams has, with a wistful look in Ronald Reagan's direction, endorsed Wallace for President. Williams, who lost 28 years of Congressional seniority because he supported Barry Gold-water in '64, has passed along the word that he doesn't care a bit whether his Wallace endorsement means the state's delegation won't get seated in Chicago. But Senator James Eastland, who would much prefer to keep on reasonably cordial terms with his Washington colleagues, has been quietly arranging to polish the state party's image by including a handful of Negroes among the delegates.

So Alabama will likely send a lily-white delegation North, while Mississippi may manage its first integrated group. Both are headed for trouble.

Washington attorney Joe Rauh, who acted as counsel for Negro challengers in '64, is taking a leading hand in behind-the-scenes work to put together the challenges in both states. In Alabama, the likely organizers include former state attorney general Richmond Flowers, who won the lasting love of local Negroes by seeking their votes in his unsuccessful gubernatorial fight against Lurleen Wallace. He will be working closely with leaders of the only state-wide Negro political organization, which is dedicated to supporting the national party.

The Mississippi situation is more muddled. There is now a 50-50 chance that there will be two challenging delegations from the state. Lawrence Guyot, head of the militant Mississippi Freedom Democratic Party which staged the '64 challenge, has vowed to send another mostly Negro delegation to Chicago. Rauh, however, is working this time with Negroes and white moderates associated mainly with the Mississippi Young Democrates and the National Association for the Advancement of Colored People.

There is a long history of rancor between the MFDP and the Young Dem-NAACP coaliiton. A meeting between leaders of the two groups last month resulted in little agreement on whether to join forces in a challenge, but another meeting is scheduled for next week.

An MFDP delegation would stand no chance of being seated. It embarrassed the party in '64, squawked loudly over the compromise, and is now so fragmented that it could not possibly claim to represent more than a half dozen counties.

The Young Dems and the NAACP, on the other hand, stand an excellent chance of setting up a formidable delegation. It is probable that a number of powerful industrialists and Delta planters who favor President Johnson will lend their support to a challenge.

The idea would be to prove that the state party opposes Johnson and integration. The insurgents may try to win control of a convention in one or more of the heavily Negro counties. From each county convention, they could send insurgent delegations to the state convention. There, they could offer a series of embarrassing resolutions--supporting LBJ, equal opportunity, full Negro participation in party affairs, and whatever else is dear to the national Democrats and anathema to Mississippi.

The challengers would then hold county elections of their own--in as many as 60 counties--choose a state convention, approve the resolutions, and dispatch them and a well-integrated delegation to Chicago.

At least two members of the Democratic National Committee have been closely involved in developing the plan. Says Louis Martin, the party's top Negro official, "It's got a damn good chance."

If so, it will present anti-Johnson forces with an awkward dilemma. They will want to stress their unity with the nation's Negroes. But the primary concern of the Alabama and Mississippi Negroes coming to Chicago will not be to end the war or to dump Johnson. They will support Johnson, they will be repeating again and again that they support him, and they will be doing everything in their power to get inside the convention hall in order to cast ballots for him.

Should they succeed, the ecstatic delegates are more than likely to urge local Negroes to stay home and watch the festivities on TV. They will not want anyone tinkering with the convention that seated them. The fact is, the Southern insurgent wing of the Democratic party ardently supports Johnson.

"I don't understand their gonadal urge to go up there and vote for Lyndon," sighs a key organizer of the Mississippi challenge. "But they don't give a damn about the war, and they love him."