That tension is greater than usual when the contest is for the nomination of a political party dominated by a large number of newcomers to politics motivated by strong opposition to current policies.
That was the case 40 years ago when members of the peace movement, opposed to the Vietnam War, became the largest and most highly motivated part of the Democratic party.
And it is the case this year because the political newcomers referred to as the Tea Party have become the most highly motivated part of the Republican party. They are opposed to the Obama Democrats' vast expansion of the size and scope of government and to any policy that abets it.
The Republican candidates, who had their first real test in last night's Iowa caucuses, have long political records, going back to the 1970s in the case of Newt Gingrich and Ron Paul, and all of them (or all but one) have taken stands in tension with the principles of this cycle's Republican voters.
Some have backed a mandate to buy health insurance -- a conservative proposal in the 1990s. At least one championed spending earmarks. Some are vulnerable to charges of crony capitalism. Some have disparaged or declined to support the Medicare reforms in House Budget Chairman Paul Ryan's budget package.
Ron Paul, a libertarian on economics, is far out of line with most Republicans on foreign policy. The one candidate most in line with the Tea Party, Michele Bachmann, is the one with the thinnest resume, with five years as a backbencher in the House of Representatives.
The Republican race has been described by many as the rise and fall of various conservatives as the alternative to the supposed moderate Mitt Romney. But Romney has been emphasizing Tea Party themes, invoking the Founding Fathers and contrasting Obama's entitlement society with his merit society.
As this was written, the final results were not yet in from Iowa. But with 90 percent of the vote counted, Mitt Romney and Rick Santorum were running neck and neck, with Ron Paul in third and Newt Gingrich, Rick Perry and Michele Bachmann far behind.
The entrance poll showed Romney running not far behind Paul and Santorum among the nearly two-thirds of caucus-goers who said they supported the Tea Party movement, and winning about half the votes of the one-third of caucus-goers who said they wanted to support the most electable candidate.
Evidently Romney is not seen as totally unacceptable by Tea Party sympathizers and has a considerable advantage on electability.
The race now goes to New Hampshire next Tuesday and South Carolina January 21. Santorum, who has had negligible support in New Hampshire, will surely get a bounce from his late surge in Iowa, but the Granite State has a much more secular electorate and Romney's big lead in the polls there seems to be strongly based.
Ron Paul will get a share of the non-Romney vote and so may Jon Huntsman, who skipped Iowa and staked his all on New Hampshire.
The old saying is that three candidates get a ticket out of Iowa to New Hampshire. Two who didn't -- Rick Perry and Michele Bachmann -- say they will go on to South Carolina instead.
Newt Gingrich, who once looked to be competitive with Romney in New Hampshire and had a big lead in South Carolina polls before Christmas, will undoubtedly soldier on and hope he can reverse his slide with good debate performances.
It is too soon to say that Romney has a clear flight path to the nomination. But the tensions between his past record and current Tea Party orthodoxy have not proven to be disabling, because the other candidates are to varying extents out of line with that orthodoxy as well.
Romney has had the benefit of luck -- several strong competitors declined to run or dropped out -- but also showed skill in deciding last month to ramp up his Iowa campaign. But he has yet to show he can beat an opponent one-on-one.
Michael Barone,The Examiner's senior political analyst, can be contacted at firstname.lastname@example.org. His column appears Wednesday and Sunday, and his stories and blog posts appear on washingtonexaminer.com.