WASHINGTON — For years, Republicans have run for office on promises of cutting taxes and bolstering business to stimulate economic growth, pledging allegiance to a Reaganesque model of conservatism that has largely become the party’s orthodoxy.

But this election cycle, the Republican presidential candidate who currently leads in most polls is taking a different approach, and it is jangling the nerves of some of the party’s most traditional supporters.

The tendency of that candidate, the billionaire developer Donald J. Trump, to make provocative, headline-grabbing speeches has helped obscure an emerging set of beliefs: that he would raise taxes in certain areas, particularly on corporations that he believes do not act in the best interests of the United States.

In recent weeks, Mr. Trump has threatened to impose tariffs on American companies that put their factories in other countries. He has suggested he would increase taxes on the compensation of hedge fund managers. And he has vowed to change laws that allow American companies to benefit from cheaper tax rates by using mergers to base their operations outside the United States.