Whether Mr. Trump prevails or the party is left to rebuild from defeat, these conservatives in think tanks, advocacy groups and the news media — and a few in political office — will be pressing for a new agenda: to update the Reagan-era playbook with an eye to working-class voters without a college education who form the Republican base. Ronald Reagan’s notions that policies that benefit the rich and big business lift all incomes now appear outmoded in an era of rising wealth inequality and stagnant wages.

The challenge to the party could be every bit as contentious as Mr. Trump’s ascent has been. Beyond conservative think tanks and activist circles, the new breed of conservatives has not made significant inroads among House Republicans, for instance. And even these Republicans do not agree on everything.

But some common ideas suggest their proposed road map for the party:

• Reject additional tax cuts for those making more than $250,000 a year, but expand breaks for low- and middle-income workers through tax credits for children, the earned-income tax credit or a new wage subsidy using tax dollars to bring low wages toward the local median level.

• Promote the benefits of global trade agreements, but help displaced workers.

• Rule out fully privatizing Social Security and Medicare, and reassure workers they will be exempt from cost-cutting.

• Acknowledge that universal health care is here to stay, but push for market-oriented changes.

• Disavow mass deportations and promote the economic benefits of legalizing longtime workers who are in the country illegally, but reduce the legal entry of less-skilled immigrants.