"You can't tell the players without a scorecard, and this year there's no scorecard." That comment was made by former alderman Bill Singer of this city about the presidential race in this state.

All the usual patterns here have been smashed, and whoever carries the state will do it with an amalgam of bits and pieces that cannot constitute a governing majority. In that sense, Illinois, as so often in past presidential races, mirrors the national condition.

The usual pattern here centers on a battle between Cook County, including Chicago, and downstate, including everything else in Illinois. Cook County was dominated by the potent Democratic organization that reached its heights under the late mayor, Richard Daley. Downstate was Republican. The issue was whether the scattered Republican communities could amass enough votes to overcome the concentrated power of the machine.

In the past, outcomes tended to be close. They also ran parallel to the national result. Illinois supported every winner from Harding in 1920 through Nixon in 1972. The margin the state gave to Ford in 1976 was 51 percent -- only a point off the national average.

But the Cook County organization, after years of hidden decline, has now fallen apart. The visible symbol is the race for state's attorney of Cook County by the Democratic nominee, and son of the former mayor, Richard M. Daley. The present mayor and Democratic leader here, Jane Byrne, is supporting the Republican candidate, Bernard Carey. The coming apart of the Democratic bastion has found a Republican counterpart. The "collar suburbs" encircling Chicago -- Lake, Kane, Dupage, McHenry and Will counties -- have emerged as the dominant component of the downstate vote. But while generally Republican, the suburban voters frequently switch to support Democrats whom they perceive to take their distance from the Chicago machine. Thus they helped elect Adlai Stevenson governor in 1948 and kept the Senate seat for his son in 1970 and 1974.

To complete the mixup, each presidential nominee this year in some degree repels his normal backers while exerting an appeal in the stronghold of the other. The white, largely Catholic, working-class voters of the big city are prime victims of inflation and, in some cases, unemployment. They are not keen on Jimmy Carter, the less so as they tend to sympathize with Ronald Reagan's conservative stance on social issues such as abortion.

Thus, the Tenth Ward, in southeast Chicago, has heavy unemployment because a local steel mill has been shut down. "I'd like to win by the usual margin of 10,000 votes this year," says the Democratic ward leader, Edward Vrdolyak. "But this year we'll be way under that."

The 41st Ward on the northwest side of town, near O'Hare Airport, presents a similar case. Alderman Roman Puchnski says the older voters will stay Democratic. But he believes that "the young people are hurting from inflation. They can't get loans to buy houses. They may not vote."

Gov. James Thompson, who leads the Republican effort in the state, actually faults Reagan for not going after the blue-collar vote on the economic issues more energetically. The governor says Reagan should spend less time in Republican areas and more in the traditional Democratic wards of the city. "He ought to run in Chicago," Thompson said in an interview, "as if he were running for alderman."

Conversely, suburbanites have been scared off Reagan by his tough stance on foreign policy. William Morris, the Democratic mayor of Waukegan, in Lake County, believes Carter will win more than 40 percent of the vote against a norm of 37 percent for the Democrats in Lake County. "Most of the people here have teen-age children," he says. "They think Reagan means a stronger military and that might mean war."

In DuPage County, which is the richest in the state and one of the biggest, Ford won in 1976 with more than 70 percent of the vote. The Democratic leader in the county, Rep. William Redmond, cites the war issue and says: "Reagan isn't doing nearly as well in DuPage as Ford did."

The overall outcome in Illinois remains doubtful. Polls show the two leading candidates running neck and neck. The number of undecided voters is large, and John Anderson is very much a factor. But whatever happens, Illinois -- the bellwether of all bellwether states -- bears witness to the atomization of the electorate. Opinion in this state, like opinion in the country, has been broken down into so much tiny, ill-fitting flak that no one can put together a base for a coherent policy.