Republican presidential candidate Donald Trump speaks to participants in the Kansas Republican Caucus in Wichita on March 5. (Dave Kaup/Reuters)

What we are seeing in the continuing march of Donald Trump toward the Republican presidential nomination is the power and significance of political entrepreneurship. If you want to become president (or senator or House member), you don’t need the permission of either party. You just announce, comply with the legal requirements for filing and launch your campaign.

You are the political entrepreneur. To help you, there’s a thriving industry of campaign consultants, pollsters, media buyers, digital experts, fundraising and direct-mailing companies. In 2012, there were 1,765 of these firms that oversaw $3.6 billion in campaign spending, reports political scientist Adam Sheingate of Johns Hopkins University in his new book, “Building a Business of Politics.”

“Who sent us the political leaders we have?” asked political writer Alan Ehrenhalt in his 1991 book, “The United States of Ambition.” “There is a simple answer. . . . They sent themselves.” Almost anyone can play. In this campaign, Republicans had at least 17 candidates for president, and the Democrats still have one long shot, Bernie Sanders.

All this seems so normal that we rarely question it. But the rise of political entrepreneurship — depending mostly on yourself for electoral success — represents a major upheaval in U.S. politics.

Through most of the 19th century and until the late 1960s, officeholders depended on political parties. Party leaders — so-called “bosses” and their political “machines” — dominated the process, especially in densely populated cities with large ethnic neighborhoods. The parties screened candidates for most offices, reminded supporters to cast a straight party ticket and got out the vote. In return, some party regulars got patronage jobs.

As for presidential nominees, they were selected at party conventions. In the 19th century, presidential primaries didn’t exist; Oregon created the first in which parties were obligated to accept the primary winner in 1910, reflecting the Progressive Era’s pervasive criticism of governmental secrecy. Still, primaries spread slowly. Even in the 1960s, state political leaders, who usually controlled their delegations, retained much power in picking a nominee, says political scientist David Karol of the University of Maryland.

To enhance their bargaining power, “many state delegations [arrived at conventions] pledged to favorite sons or uncommitted,” Karol says. Negotiations ensued until one candidate achieved the necessary majority. In 1860, Abraham Lincoln was nominated on the third ballot; in 1932, Franklin D. Roosevelt was nominated on the fourth.

In this system, Trump would have played no role. He holds no elective office and is not a war hero (a sometimes-qualification for the White House). He has no allegiance to political power brokers. But under the new system, the party power brokers lost power.

Party dominance crumbled under many pressures: radio and television, which created new ways for candidates to reach voters; civil service reform, which limited patronage jobs; suburbanization, which drained ethnic neighborhoods; the rise of campaign polling — starting in the 1936 election with George Gallup — which created new sources of political information; and hostility toward “corrupt” bosses.

The Democratic Party delivered the fatal blow after the 1968 election when it adopted rules effectively forcing state parties to hold presidential primaries or open caucuses to allocate their votes for presidential candidates. Republicans enacted similar “reforms.”

Although the new system is more democratic than the old, it hasn’t produced better results. By reducing the influence of party leaders, it favors campaigning skills over governing skills. Relatively inexperienced candidates benefit. This helped elect Presidents Carter and Obama, but once in Washington, they had trouble governing. Trump’s bombastic campaign rhetoric is an extreme example of the same tendency. Entrepreneurial politics has not elevated the level of debate or the quality of candidates.

We have moved from party-based politics to personality-based politics. Image and ideology count more than ever because candidates — at all levels of government — try to differentiate themselves from their rivals, both inside and outside their party. Our politicians are increasingly freelancers, dependent on their own hard work, political savvy, fundraising ability and public-relations skills.

Because candidates heavily determine their own victory or defeat, campaigning has become a full-time way of life, with all its extravagant and unrealistic promises. This feeds a cycle of disillusion, as voters first have their expectations raised and then dashed. In this self-absorbed climate, party discipline suffers, and it’s hard to craft pragmatic bipartisan compromises.

There is little public support for reverting to more closed nomination processes, where now-derided party elites would assume a bigger role. They have been overtaken by changes in public opinion and technology. Still, the confusion and dissatisfaction with the present campaign makes you wonder whether the old-time bosses were really so bad after all.

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