A third party only achieves success in replacing a major party when both major parties fail to adopt a view held by nearly 50 percent of the voters. Anti Slavery is an example of an issue that made the Republican Party.
You don't worry until you see a substantial change in your solid base voters. Then you'd better find out why.
Both parties have had this in recent years, largely the result of their run-to-the-center general election strategie
BULL CRAP!!!! There is zero evidence to back up that y statement.
Strom Thruman tried to pull the Southern Conservative base from liberal Harry Truman in 1948. Dewey and the Media were certain that would cost Truman the Presidency. The base was there for Truman. In case you didn't notice Trumans hard turn to the left on civil rights did not cost Harry the election. He held enough of the South to win the election. Dewey played to his base... by not going to the center at all, It cost Dewey the election in 1948. It took Richard Nixon nearly 20 years and a defeat by JFK to figure that out.
Everert Dirkson stood at the Republican convention podium in 1952 telling the delegates if they abandoned conservative Taft for the liberal Ike, the base would abandon the Republican party and stay at home. Everett as usual was full of CRAP. Centrist Ike easily beat a vert liberal Stevenson. Ike had the Republican base in both 52 and 57. It did not matter that Ike was a centrist what mattered was that Stevenson was a flaming liberal.
There was a lot of talk that the catholic JFK could not hold the protestent Southern Democratic base.. but if you look at 1960 Results JFK won... The small amount of lost base did not matter. JFK got more of the Democrat base than did the much more liberal Stevenson. Nixon got the base... Nixon lost too much of the CENTER. He vowed to go for the center if he ever got the nomination again.. He ran to the center in 68 and won.
If you look at 1964 you will find the Republican candidate that the Republican base loved. The base loveing Goldwater did not do as well as the "baseless" Nixon did in 1960. To Goldwater the base was not worth a warm pitcher of spit although they tried their best to elect him. The center is the game. It always is the game. It always has been.
The Democrat base loved McGovern in 1972 ....That was disaster city when he ran against Richard Nixon. The center didn't go for McGovern and he lost. The republican base turned out for Nixon in both 68 and 72. The center did too.
Neither Jerry Ford or Carter appealed to their bases much but Carter won in 1976. There is no evidence that the base did not turn out for Jerry or Jimmy. It was the center that did not turn out for Jerry. They turned out for Carter instead.
Reagan spent the entire campaign of 1980 running away from the base and running to the center. The major themes of the Reagan campaign were right out of the Democrat play book. YOu can make a good case Reagan ran to the LEFT. a: Reagan constantly reminded voters he was a former UNION PRESIDENT. Imaging how much the Republican base loves Union Presidents. b: Reagan reminded voters he was a huge fan of FDR and a former Democrat. In the debate with Jimmy Carter he mentioned it. Reagan said he still held the same positions he did when he was a Democrat. His exact words were, "My Views have not changed!" Imagine how the base loved that. c: Reagan constantly reminded voters his economic plan was identical to the JFK plan of 1961. In case you never noticed JFK was a Democrat. It may surprise you to note that JFK bore an amazing resembliance to Teddy Kennedy.. Some say they may have been brothers.
Bush Sr. Ran hard to the base...Remember... "READ MY LIPS.. NO NEW TAXES..." Dumb move. Dukakis was the quintessencial base man. He got fewer numbers of the center in 88 than Bush 41. Buth the center deserted Bush 41 in 1992 for some guy who called himself a NEW Democrat. It was Clinton who ran to the center in 92 as the centrist NEW DEMOCRAT.
Clinton never ran to the base. HE RAN AS A NEW CENTRIST DEMOCRAT. Gore did not run to the center, Nader scared Gore into running to his base. It cost Gore the Presidency.
Bush has been running to the center since the day he got the nomination. Gore in trying to win the NADER votes ran to the base and got beat.
You post intuitive feelings that the base may not turn out unless they get what they want, but that is only a danger when the other parties candidate is on to your side of the center. As long as the Democrats run well to the left of center, there is zero danger in a Republican running to the center.
There are are no cases in modern history where pandering to the base does anything except insure defeat.
AS far as tracking the party data basses they just do not show what you pretend to say they show. The most important state for presidential elections is OHIO. No one wins the presidency with out winning OHIO.
The correlation you are trying to make is the exact opposite of the truth in OHIO. The more the Democrat candidate runs to the center, the smaller the Republican base turn out. A centrist Democrat does not scare the more leftist registered Republican (Clinton), as much as a left wing (Dukakis).
The secret to getting the Republican base out is painting the Democrat candidate as a real liberal. If the Republican base is scared of the Democrat candidate they will come out to vote. If the Democrat is a NEW DEMOCRAT from the more conservative South, he does not scare some of the more left Republican base and they don't turn out.