How Reagan won 49 states

[Fuzzy Bear]

Several reasons apply here:

1.  The improving economy.  This has been mentioned.

2.  Mondale explicitly saying he'd raise taxes.  That was stupid.

3.  The continuing Cold War conflict with the Soviets, coupled with the perception of the dominant faction of the Democratic Party as naïve peaceniks, gave the Presidential GOP a huge structural advantage.

4.  Continuing white racism in suburbia kept the suburbs Republican.  Blacks moving into white neighborhoods in suburbia was a huge issue for "dog whistle politics" through the 1980s.

5.  America was far, far more socially conservative in 1984 than it is today, and on every front.  Reagan was a master at telling ordinary Americans that there was nothing wrong with their social worldview, and a master at pointing out Democratic criticism of that worldview.

6.  Mondale and Ferraro (who was a terrible candidate) came off as pandering on more than one occasion.  The Ferraro pick was viewed as pandering to women, and came after Mondale interviewed candidates of a wide-ranging span of ethnic origins, some of whom were royally unqualified (e. g. Philadelphia Mayor Wilson Goode, who had only been on the job less than a year, and was not considered a successful Mayor.)

7.  Reagan was likeable and projected strength in ways that social media makes impossible today.

Those are the generalities.  Now for some specifics:

In MASSACHUSETTS and RHODE ISLAND, Reagan benefitted greatly from his Irish heritage.  Though not Catholic, Reagan was descended from a line of Irish Kings, a fact made known at the beginning of his Presidency.  Reagan got the votes of Yankee Republicans far less conservative than he was, but he also got the votes of socially conservative Irish Democrats in Boston and throughout New England. 

In HAWAII, Reagan was an incumbent President.  Hawaii had high support for incumbents, and was very pro-military during the Cold War.  Hawaii's margins for Nixon in 1972 were above his national averages.

NJ, MI, MD, and most Northeast and Midwest suburban communities had major issues with school busing for racial integration in the 1960s and 1970s.  This issue was a real non-starter for white Democrats and something that many white Democrats blamed the Democratic Party for. 

NJ also had tax issues.  NYC middle class folks fled the city for NJ and its absence of a state income tax, only to have a Democratic Governor impose on in the late 1970s.  Through the 1980s, tax issues galvanized NJ suburban voters in what was an almost entirely suburban state.