Yes, in the south in the 50s. There was no Republican party; Thurmond, the sitting senator, just had to beat a democrat challenger. It can happen sometimes in a state, especially south carolina in 1954. It can’t happen in a national presidential election. You won’t even get one state as a write in. Might be able to get some states as a third party candidate on the ballot, but the 3 way split favors the major parties. Best to organize and put the RNC out of business first.
That wont be happening this cycle.
Best bet is for Trump/Cruz to take it over .
The other alternative are far worse.