Ross Douthat mostly says everything that needs to be said, but let me just state it very clearly — the idea that Ronald Reagan’s charisma and sunny disposition won landslide victories for Barry Goldwater’s substantive views on the size and scope of government is false. Very false.
Reagan was, famously, the political beneficiary of a backlash against the liberalism of the 1960s and 1970s. The important thing to remember about this is that unless you think people were lashing back against the Peace Corps, this was a backlash entirely against programs that didn’t exist during Barry Goldwater’s 1964 campaign. It was only after Goldwater lost that “welfare as we knew it,” Medicare, Medicaid, major federal involvement in education, federal environmental policy, federal consumer safety regulations, affirmative action, etc. came into exist. Reagan’s political mobilization was aimed at a subset of this post-Goldwater flowering of big government. He didn’t tilt against Medicare, by far the biggest Great Society program. And he certainly didn’t campaign for the repeal of the New Deal (indeed, he repeatedly explicitly disavowed any intention of doing so).
The Goldwater-Reagan similarity is that they both led “conservative” factions of the GOP against “accommodationist” factions. But between 1964 and 1976 the country experienced a massive policy revolution that shifted the status quo way, way, way to the left of where it had been. Reagan then simultaneously shifted the GOP to the right of where Gerald Ford had initially positioned it while shifting the conservative movemenet to the left — to acceptance of a federal responsibility for retirement security and quality education, to acceptance of the Civil Rights Act (opposition to which was, of course, Goldwater’s only reliable vote-getter in ’64), and to acceptance of popular middle class entitlement programs.