[2] Before the era of rapid international transport or essentially instantaneous communication (such as telegraphy in the mid-19th century and then radio), diplomatic mission chiefs were granted full (plenipotentiary) powers to represent their government in negotiations with their host nation.
Permanent missions at a bilateral level were chiefly limited to relations between large, neighboring or closely allied powers, rarely to the very numerous small principalities, hardly worth the expense.
Diplomatic missions were dispatched for specific tasks, such as negotiating a treaty bilaterally, or via a conference of plenipotentiaries, such as the Imperial Diet of the Holy Roman Empire.
Given how heavily entrenched apartheid was in the South African legal system at the time, de Klerk needed to nullify many previous bills and pass many new ones, making a series of individual referendums impractical.
Consequently, as a practical solution to the political deadlock, de Klerk held a referendum on 17 March 1992 to ask the white South African electorate to give him plenipotentiary powers.