David Gergen is a senior political analyst for CNN and has been a White House adviser to four presidents. A graduate of Harvard Law School, he is a professor of public service and co-director of the Center for Public Leadership at the Harvard Kennedy School. Follow him on Twitter: @david_gergen .

(CNN) Columnist Edward Luce argued Monday in the Financial Times that Donald Trump has created a new brand in politics: an upraised middle finger. Later that day in Iowa, voters rejected Trump the candidate but stole his brand: They flipped a bird at the American political elite.

Three of the top four vote getters on the Republican side -- Ted Cruz, Trump and Ben Carson -- ran staunchly anti-establishment campaigns and together captured some 60% of the total vote. Among Democrats, Bernie Sanders won basically half the total votes by campaigning for a revolution.

Voters on both sides were sending a clear message of no confidence in the economic order. Who can remember a presidential campaign in which the most extreme candidates have done so well in the first round?

It is true, of course, that each party may ultimately embrace a nominee closer to the center. That is obviously the case with Democrats where Hillary Clinton remains the favorite, and Marco Rubio's surprisingly strong showing will encourage GOP elites to believe they, too, can secure the nomination for a more moderate candidate.

But Iowa will still have consequences. Just for starters, Sanders' strength will likely draw Clinton even further to the left on issues. She has to find a way to close the enthusiasm gap with Sanders, and one way to do it is to adopt more of his agenda. It will not be lost on her that she will need Sanders' support in a general election campaign.

Republican establishment folk will continue to be terrified of a Cruz candidacy, but they, too, cannot ignore strength on the extremes -- and the likelihood that Cruz will continue to do well in red state primaries. (Texas alone will have more delegates than Iowa, New Hampshire, Nevada and South Carolina together). So, even as Republican leaders try to unite the party behind an anti-Cruz candidate -- most likely Rubio -- they will also be extending an olive branch to the far right.

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More fundamentally, Iowa could open the way to a new, more extreme American politics. Much of the anger and frustration we see among voters these days trace directly to the sluggish growth of the economy over the past 10 years. Unfortunately, most economists think we won't be snapping out of that soon, no matter who is elected in November. What that may well mean is that Iowa could be a forerunner of politics to come.

It is odd that caucuses in Iowa could have so much import. The folks who voted there Monday are only a tiny fraction of the American electorate. Indeed, they are only a small fraction of the Iowa electorate itself: Cruz won the GOP caucuses with some 50,000 votes -- about 2% of the state's registered voters

Still, big changes in America often come from small towns and hamlets. And so it may be with this year's first vote of the 2016 race.