If Reagan dies in 1981? Hmm, well the big question is who would get nominated as Bush's veep? For the sake of irony let us say it is Dick Cheney. Four years later does Bush get re-elected? Possibly he can use Reagan's call to arms to get the sympathy vote, and lets face the DNC is likely to give their nomination to Mondale, only in ttl, Mondale does not get smoked, but still loses.
Relations with the USSR are warming but not as hawkish as they were under Reagan, and Gorbachev is slower to implement some of his programs.
In 1988 Dick Cheney campaigns for and wins the GOP nomination, but the DNC decide to run someone tougher, lets say due to butterflies, Mario Cuomo agrees to run for President and wins a convincing victory over Cheney who has the personality of a rock. Cuomo selects Al Gore as his veep.
Cuomo wins re-election in 1992 and in 1994 watches as communist regimes begin to fall in Eastern Europe, but not Russia, he also oversees the Second Korean War (this nearly occured in 1994 in OTL) and by 1996 the US controls much of the Korean Peninsula, PRC complains and rattles its saber, but its economy has become to intertwined with the American economy to risk war. Due to the victory in the Cold War, and in the Second Korean War, and a healthy economy Al Gore defeats Bob Dole in the most boring election in human history in 1996. The DNC remains in control of Congress, but the country has other problems.
In 2000 after 12 years out of office, the GOP wins back the White House riding on John McCain's coattails. There is no September 11, but several foiled plots to destroy American landmarks by Al Queda, the US and its closest allies begin air strikes in Afghanistan but have difficulty getting Pakistan to support the operation. John McCain wins reelection in 2004.