BUSH VERSUS GORE: Is it the battle for president in 2000? No, it was the Houston mayoral runoff in December. When Vice President Al Gore, with his eye on the Democratic nomination two years hence, came to a fundraiser for eventual winner Lee Brown, Bill Clinton’s first drug czar, the nonpartisan race suddenly took on very partisan overtones. First Barbara Bush and then former president George Bush himself made TV ads for Brown’s opponent, Rob Mosbacher, the son of Bush’s Secretary of Commerce. The result: Mosbacher’s previously moribund campaign took off, and he cut Brown’s double-digit lead in half. Meanwhile, in Austin, the retirement announcement of Attorney General Dan Morales (see Behind the Lines: “The Last Whimper,”) was great news for George W. Bush, who is the early GOP front-runner for 2000. Texas Republicans are already gloating that they can win all nine statewide executive offices from governor through railroad commissioner this fall and capture a majority in the state House and Senate. When Bush ran against Ann Richards in 1994, Democrats controlled both houses of the Legislature and every statewide executive office except agriculture commissioner and one railroad commissioner. If the GOP indeed wins the whole bundle on November 5, the message for Republican presidential primary voters would be that Bush is not only highly electable but also has long coattails.