RANCHO MIRAGE, Calif. (Feb. 26)—Economic growth of 3 1/2 to 4 percent in the second half of the year is in the cards, the chief economist of the U.S. Chamber of Commerce said at the Rubber Manufacturers Association's annual general meetings in Rancho Mirage. Martin A. Regalia, vice president of economic and tax policy, said a recovery sparked by President George W. Bush's tax cut proposal will occur, but only if that stimulus package essentially is passed, and only if a war in Iraq qoes well and quickly. If the war drags on, if oil production is disrupted elsewhere in the Persian Gulf, things would be different, the speaker said. If that's the case, "We're going to get oil prices as high as around $80 a barrel, and we're going back into recession," he told the audience of rubber company senior executives meeting at the Westin Mission Hills Resort, outside Palm Springs.