President Clinton is handing the job of selling the controversial Mexico trade agreement to Chicago lawyer William Daley, a shrewd negotiator with longstanding ties to the labor unions that vehemently oppose the pact.

Clinton planned to name Daley as his "NAFTA czar" Thursday before leaving Washington for an 11-day vacation on Martha's Vineyard, according to two White House officials who spoke Wednesday on condition of anonymity.The 44-year-old attorney is the son of the late Richard J. Daley, Chicago's mayor of 21 years, and the brother of current Chicago Mayor Richard M. Daley.

Clinton inherited the North American Free Trade Agreement from the Bush administration and plans to seek congressional approval this fall now that he has negotiated side agreements on labor and environmental standards with Mexico and Canada.

Those deals were designed to allay the fears of labor unions that have protested that Mexican workers are exploited with low wages and lousy work conditions, and of environmentalists who say the country's manufacturers put profits over environmental protection.

"Nothing like this has ever been found in a trade agreement before," Clinton said of the side agreements. The provisions allow for sanctions if Mexico fails to keeps its end of the bargain and "ensures that workers on both sides of our border can benefit," Clinton said.

But labor and its top allies in Congress were not swayed by the side agreements and have vowed to defeat the trade pact when Clinton submits it for ratification. They have a vocal ally in Ross Perot, the Texas businessman and 1992 independent presidential candidate who is running a campaign against the trade deal.

With promised Republican help, Clinton appears to have the votes to win Senate approval, but the outlook is more uncertain in the House, where much of the Democratic leadership is opposed to NAFTA.

Daley's job will be to navigate those treacherous waters, trying to win passage of the trade agreement without causing too much internal friction within the Democratic Party.

He is known as a shrewd political operative and negotiator with solid relations with labor unions stemming from his political ties and tenure as president of Chicago's Amalgamated Bank, which was founded in 1922 by the Amalgamated Clothing Workers of America.

While it opposes NAFTA, "the labor movement never holds anything against the other team's foot soldiers," said AFL-CIO spokesman Rex Hardesty.

The Daley brothers were early Clinton supporters, helping the then-Arkansas governor to a critical win in the Illinois Democratic primary and again to victory there in November, the first by a Democratic candidate in the state since Lyndon Johnson.

William Daley was then considered for the Clinton Cabinet and was a finalist for transportation secretary before Clinton tapped Federico Pena, the former Denver mayor.

- William Daley