RUSSELL, Kan. (AP) _ The mystery solved, Republican presidential candidate Bob Dole hoped to debut the Dole-Kemp ticket with a red, white and blue rally at the rural courthouse where his political career began.

But a drenching rain threatened to move the festivities to a covered exposition hall at the fairgrounds. Dole emerged from his house this morning briefly to look up at the sky as he awaited the arrival of former housing secretary and New York congressman Jack Kemp.

Dole had hoped to keep his choice of vice presidential running mate a surprise until today's event. But even as American flags were being stationed Friday along Main Street for today's formal announcement, GOP activists were voicing enthusiasm about the selection of Kemp, a sometime Dole antagonist.

Kemp arrived at a small airport about 35 miles from here early today and spent the night at a motel in Great Bend.

Nelson Warfield, Dole's press secretary, said that the former Senate majority leader reviewed newspaper clips this morning announcing his selection of Kemp. He said Dole was pleased with the coverage of his decision and particularly ``impressed that (former New York Gov.) Mario Cuomo had called the choice formidable.''

Campaign sources said Dole made the offer _ and Kemp accepted _ in a 15-minute telephone call late Friday night. The pair planned to meet at Dole's boyhood home before the rally and a triumphant entrance at the GOP's San Diego convention site on Sunday.

``We've got a veep ... the curtain goes up on the drama of taking the White House back from Bill Clinton,'' spokesman Nelson Warfield said after Dole placed the call from his living room.

``I can't tell you who the other party was, but I can tell you he was extremely enthusiastic. You could hear him through the phone.''

But two sources familiar with the conversation told The Associated Press that Kemp was Dole's choice, ending a months-long review in which Dole sifted through a handful of popular governors and three former Senate colleagues before turning late to Kemp.

Just a month ago, Kemp predicted his stormy relationship with Dole _ and a history of deep differences over economic policy _ would keep him from being considered. But by Friday, the 61-year-old former pro football player's tune had changed. ``Quarterbacks are always ready,'' he declared.

The Dole team also was ready, arriving here with a vice presidential staff already assembled and former Commerce Department official Wayne Berman at the helm as manager. Veteran GOP strategist Charlie Black, who ran Texas Sen. Phil Gramm's unsuccessful primary bid this year, was also drafted.

Democrats greeted Kemp's selection with footballs bearing the slogan: ``Hail Mary Pass.'' But one, former New York Gov. Mario Cuomo, called the ticket ``formidable'' and said Kemp could hurt Democrats by appealing to minority voters.

Dole, who had joked about sneaking his mystery date through the back door, clearly delighted in prolonging the guessing game. ``Beats working,'' he said.

The Dole campaign, stuck far behind President Clinton in horserace polls, was counting on a bold vice presidential choice and a smooth convention next week to excite doubting Republicans.

Indeed, as word of Kemp's selection spread through San Diego, where Dole-Kemp T-shirts were already on sale, reaction among the GOP faithful was overwhelmingly positive.

``We now have a forward-looking, dynamic ticket. It will truly excite the country,'' said former Dole rival Steve Forbes, the flat-tax advocate whom Kemp endorsed during the primaries.

But a walk through downtown Russell suggested Kemp was not a surefire hit with all voters.

``Who? I don't know him. It should be a woman. They never pick a woman,'' complained Kaylee Karst, a clerk at Don Dawson Pharmacy.

Pharmacist Mary Sturdy of nearby Hays chimed in that ``since he (Kemp) is from the East there's not a whole lot known about him here.''

Some party activists worried that Democrats would exploit the running mates' differences on key conservative issues. Kemp is opposed to term limits, supports affirmative action and has criticized tough immigration policies.

Dole and Kemp have been rivals _ and antagonists _ for years. They were unsuccessful candidates for the 1988 Republican presidential nomination, and both were passed over as a running mate for George Bush.

At the root of most Dole-Kemp feuds has been economics: Dole is a deficit hawk determined to balance the federal budget; Kemp a supply-side apostle supporting deep tax cuts and economic growth before balancing the books.

Dole's new economic plan bridges both camps, and it was during deliberations over its $548 billion in tax cuts that Kemp emerged as a serious vice presidential contender.