U.S. Sen. Tom Harkin of Iowa flew to Chicago Friday and set a deadline just weeks away for Gov. George Ryan and Mayor Richard Daley to compromise on increasing runway capacity at O'Hare International Airport.

Harkin warned that without a speedy local agreement to reduce the record flight delays at O'Hare, ending almost two decades of stalemate in the airport-expansion debate, there is strong bipartisan support in Congress to approve legislation requiring the construction of more runways at O'Hare.

"I'm hopeful in the ensuing weeks that the local government here in Chicago and the state government will work this out and move ahead," Harkin said after a private meeting with the Civic Committee of the Commercial Club of Chicago. "If not, flight delays are no longer an option."

Declaring that O'Hare "is not the Peoria airport," the Iowa Democrat said the near-gridlock conditions in Chicago "plug up the entire commercial aviation network in this country."

He threatened to use his influence as a member of the Senate Appropriations Committee to quickly advance the runway proposal he is co-sponsoring with U.S. Sen. Charles Grassley (R-Iowa). Harkin also hinted that funding to the Chicago area in other vital areas could be held up if his O'Hare buildup plan stalled. He said he would not wait beyond June or July before acting.

Authority over extending runways or adding landing strips at O'Hare rests with the governor. The Harkin-Grassley measure would effectively relieve Ryan, who opposes expanding O'Hare, of that power. It also would direct the Federal Aviation Administration to begin the required studies on two new runways at the airport.

Harkin's appearance capped a week in which the Commercial Club ran advertisements in the Tribune and other major dailies urging the immediate construction of at least one runway at O'Hare, and a Tribune poll showed support for a new runway among residents of the suburbs near O'Hare--provided the extra capacity be used only to reduce delays, not to jam more flights into the airport.

Although some public officials and business leaders privately objected to Harkin's pressure tactics, no one questioned his authority to press the issue.

Legal experts said there is ample precedent for the federal government to override local authority on issues of national importance. It has been done many times in connection with transportation infrastructure, ranging from the condemnation of properties to make room for construction of federal highways to the overturning of local bans on jet aircraft operations and noise curfews at smaller airports.

"The 4th Amendment to the Constitution says if it's a federal issue that has a national impact, like interstate commerce, the government can pre-empt any state law to the contrary," said John Hoff, a Chicago aviation attorney who previously worked in the chief counsel's office at the FAA.

Meanwhile, there are no signs of a letup in the national pressure being applied to break the local political deadlock.

U.S. Sen. John McCain (R-Ariz.), the chairman of the powerful Senate Commerce Committee and a harsh critic of O'Hare, is to hold a hearing June 15 in Chicago on the runway capacity shortfall at O'Hare. The O'Hare bottleneck also was highlighted in an FAA report last month that said the flight-delay epidemic at the airport, where no new runways are currently planned, will worsen over the next decade.

Some Chicago business leaders said they hoped federal intervention won't be necessary.

"In the last couple of weeks, we've seen some encouraging signs that there may be movement to break the political logjam," said R. Eden Martin, president of the Civic Committee. "The governor has started to take more of a leadership role. The mayor is about to do the same."

Martin, whose business group does not oppose Ryan's proposal to build a third regional airport near south suburban Peotone, nonetheless said such an airport wouldn't make up for the capacity gap at O'Hare.

A spokeswoman for Daley said Harkin's plan to bypass local decision-making and effectively force new runways on O'Hare "may or may not be a good idea."

The mayor has acknowledged that O'Hare desperately needs at least one additional runway, but he has resisted overtures to negotiate with Ryan on Peotone, which the city and the major airlines at O'Hare oppose.

But the governor has continued to push the issue, calling on Daley again Friday to submit a plan to him for new runways at O'Hare.

"I've been accused of blocking runways at O'Hare," Ryan said. "Nobody has given me a proposal for runways at O'Hare."

FAA officials said that if the Harkin-Grassley legislation becomes law, Chicago aviation officials will be required to develop a new airfield layout detailing where the new runways at O'Hare would go, as well as a revised master plan that addresses a host of issues, ranging from the environmental impact of new runways to the financing of the airport expansion.

Harkin said he would prefer that local politicians solve the problem at O'Hare, but "we have waited over 10 years for this to happen, and I can tell you we are not going to wait any longer."

Harkin also said he wasn't worried that U.S. Sen. Peter Fitzgerald (R-Ill.), a leading critic of O'Hare expansion and a member of the Senate Aviation Subcommittee, would be able to derail the legislation.

"Sen. Fitzgerald is very vocal and very emotional about this issue, telling me I'm on the wrong side," Harkin told the Tribune's editorial board Friday. "But what the heck, that doesn't bother me."

Fitzgerald later responded that Harkin fails to understand that the Peotone airport could be built more quickly, less expensively and offer more capacity than a runway expansion project at O'Hare.

"I do think that [Harkin] wants the same thing I do, which is more aviation capacity," Fitzgerald said. "I just think he is mistaken."