Final answer:
The primary election system for choosing presidential nominees was introduced during the Jacksonian era and was first used in Florida in 1901. Over time, it has largely replaced earlier methods such as 'King Caucus' and party conventions, transferring more power to the electorate through direct primaries.
Step-by-step explanation:
The primary election as a means of choosing presidential nominees was introduced during the Jacksonian era. The system evolved from early informal congressional caucuses, known as 'King Caucus', to more democratic national conventions where grassroots movements influenced the selection of candidates. The first significant use of a primary election to select a presidential nominee was in Florida in 1901. Over time, primaries and caucuses have become the predominant process for selecting nominees, especially as reforms during the Progressive Era shifted the power of candidate selection from party bosses to the electorate.
The presidential primary and caucus system has drastically evolved since its inception, particularly with the introduction of the direct primary in the late 19th and early 20th centuries. This change has led to lengthier and more expensive campaign seasons, starting with South Carolina's adoption in 1896 for statewide elections and Florida's for presidential nominations in 1901, and has ultimately transferred more power directly to the people in the candidate selection process.