The 2016 presidential campaign seems different. Traditionally, the Republicans have nominated a known-quantity candidate with extensive government experience. The Democrats are more given to surprises.

The sudden emergence of Donald Trump as a candidate rather than constant kibitzer has further crowded an already jammed Republican race. His surge to the top of public opinion polls has made him the media focus, so far. If sustained, this will be a major shift.

The big question is whether Trump can remain the front-runner. In 2012, Michele Bachmann and Herman Cain generated early apparently strong support, only to fade.

Richard Nixon, Ronald Reagan and George H.W. Bush had years of political and governmental experience in advance of securing the nomination, two as vice president. Bob Dole, the GOP candidate in 1996, earlier had unsuccessfully sought the nomination and was the 1976 vice-presidential nominee. John McCain and Mitt Romney also fit this profile. While George W. Bush did not have such extensive senior experience before achieving the White House, his father’s precedent – and support – makes him a special case.

Two exceptions from outside the mainstream are General Dwight D. Eisenhower, the enormously successful nominee in 1952 and 1956, and Senator Barry Goldwater, the 1964 nominee defeated in the landslide for President Lyndon B. Johnson. Eisenhower developed extraordinary visibility and prestige as Supreme Allied Commander in Europe during World War II. He was not a veteran of electoral politics, but brilliant at international, Washington and Army politics.

Goldwater’s nomination reflected the growing strength of conservatives in the party, but also the special circumstances following the assassination of President John F. Kennedy. In the year after Dallas, President Johnson benefited from broad public sympathy.

By contrast, the Democratic Party at times has selected nominees who came up fast from the margins. Both Jimmy Carter in 1976 and Bill Clinton in 1992 were relatively unknown governors of smaller Southern states before securing nomination and then election to the White House. Unsuccessful party nominees Michael Dukakis in 1988 and John Kerry in 2004 were prominent in Massachusetts but not nearly so well known nationally.

Even John F. Kennedy from that state was not a broadly known national figure before 1960. For Americans at large – preoccupied with daily lives – JFK was at best only vaguely defined, and for many he seemed to come out of nowhere in that year. The Kennedy organization shrewdly both emphasized the route of the primaries, which were relatively few in number then, and sought the television debates with the much more well known Richard Nixon.

In the traumatic, violent politics of 1968, Senators Robert Kennedy and Eugene McCarthy bitterly struggled in primaries, while Vice President Hubert Humphrey secured a majority of convention delegates without entering primaries. Opinion polls consistently showed Humphrey the strongest to challenge Richard Nixon or Nelson Rockefeller, the Republican front runners.

What emerged from that terrible year was popular sentiment that process had to become more open and “representative.” Since 1968, both parties have made primaries steadily more important, and now dominant.

However, relatively few people vote in primaries. Ironically, they are not necessarily representative of public sentiment.

Traditionally, Democratic and Republican party organizations were important in determining nominees. Today, these filters and gatekeepers are largely gone. Televised melodramas followed by primaries are the result, fueled by enormous sums of money.

This has given us Trump – for the moment. Demagoguery is nothing new, but the delivery vehicles have changed.

Arthur I. Cyr is Clausen Distinguished Professor at Carthage College and author of “After the Cold War” (NYU Press and Palgrave/Macmillan). Contact him at acyr@carthage.edu.