I don’t think the republicans were ever a third party, when they formed in 1854 the Whigs were only 22 years old.
The republicans simply replaced the Whigs. Two years after the republicans first met in 1854, John Fremont came in second in the 1856 presidential race, the “know Nothings” “third party” came in a distant third with 8 electoral votes. The Whigs were pre civil war America, the party only lasted 22 years itself (1833 to 1856). The Republicans held their first convention on July 6, 1854 and four months later held 19% of the Congress and 25% of the Senate, six years later they held the majority in the Congress, the majority in the Senate, and they had the Presidency. The Republicans were never really a third party at all.
Yeah, that’s one way to think of it.
Actually, our system can only sustain two parties.
One party that is oriented toward decentralization, another oriented toward more government intervention\centralization.
Essentially its Antifederalists against Federalists under different names. Over time the names have switched, changed, reversed but it always comes down to that.