In 1972, as left-liberals led the Democratic Party to a near-unbroken 20-year run of presidential-election disasters, the late, great New York Times columnist William Safire wrote that “nothing is more certain in politics than the crushing defeat of a faction that holds ideological purity to be of greater value than compromise.”

Safire’s comment was cited this March in a trenchant Commentary article by former White House aides Michael Gerson and Peter Wehner, “How to Save the Republican Party.”

Their piece focused on the steps the party should take to avoid a fate similar to the Democrats a generation ago, while noting that the GOP has lost four of the past six presidential elections and is in danger of losing more unless it turns toward the center, as Democrats did with the presidency of Bill Clinton.

Before his election in 1992, Clinton developed his program — welfare reform, tough-on-crime, national service — through a centrist organization, the Democratic Leadership Council, unfairly derided by the left as “the Southern white boys’ caucus.”

The GOP sorely needs an equivalent of the DLC today to counter the right-wing ideological purists who dominate the House Republican Conference, terrify Senate Republicans and force GOP presidential candidates to take stances that make them unelectable.

What ideological purists — the anti-defense, anti-business, social liberal left led by Jesse Jackson and Ralph Nader — did to the Democrats, their purist counterparts are doing to the GOP. These are the pro-austerity, small-government, anti-immigrant, social conservatives led by Rush Limbaugh, the tea party, the Club for Growth and Heritage Foundation chief Jim DeMint.

The purists are willing to default on the national debt, let student loan interest rates skyrocket, deny disaster aid to hurricane-hit communities, permanently alienate Hispanics — and defeat in primary elections Republicans who waver from the right-wing line.

They have voted repeatedly to kill Obamacare without offering an alternative. And when House GOP leader Eric Cantor of Virginia proposed a measure to expand community health centers, they killed it, too.

They persistently deny the reality of climate change — even though anyone flying over the polar ice cap in summer can look down and see it’s open water. According to a Washington Post poll, 74 percent of voters favor regulation of greenhouse gas emissions from power plants, factories and autos. But not the GOP.

The purists are so partisan that even when Barack Obama adopts traditionally Republican policies — like education reform and the governor-invented core curriculum — they flip the party into opposition.

The result is that, according to a Pew Research Center poll taken in February, 52 percent of voters consider the GOP “out of touch with the American people” and 62 percent regard it as “too extreme.”

Even 36 percent of Republicans said their party was “out of touch,” and nearly a fifth said it was “too extreme.”

There exists, in fact, the makings of a Republican equivalent of the DLC — a group of Republicans seeking positive, reformist answers to the problems that ail the country and the party.

Wehner, a fellow at the Ethics and Public Policy Center, and Gerson, a Washington Post columnist, are part of it. So are Arthur Brooks and James Pethokoukis of the American Enterprise Institute; editor Yuval Levin and most contributors to his journal, National Affairs; former Congressional Budget Office Director Douglas Holtz-Eakin; and, most of the time, the editors at National Review and the Weekly Standard.

In a Wall Street Journal column in March, Brooks wrote that “conservatives are fighting a losing battle of moral arithmetic. They hand an argument with virtually 100 percent public support — care for the vulnerable — to progressives, and focus instead on materialistic concerns and minority moral viewpoints.”

In 2012, only 33 percent of voters said that GOP nominee Mitt Romney “cares about people like me” and current polls show that the party is still under water on the issue.

“The answer,” Brooks wrote, “is to make improving the lives of vulnerable people the primary focus of authentically conservative policies.”

A clutch of GOP politicians is taking up the challenge, notably Rep. Paul D. Ryan of Wisconsin, Sen. Marco Rubio and former Gov. Jeb Bush of Floria, and New Jersey Gov. Chris Christie — one of whom might well lead the GOP to victory in 2016 if he can survive a tea-party-poisoned primary process.

Ryan has developed a sorely needed GOP alternative to Obamacare and a bipartisan reform to Medicare. Rubio, Ryan and Bush are trying to convince their party to humanely reform immigration. Rubio is working to make higher education more affordable.

Probably the biggest challenge for the GOP is to develop conservative economic policies truly designed to lift poor and working-class voters out of wage stagnation and slow job growth.

Instead of tax reform that simply cuts rates for corporations and rich people, conservative writer Ramesh Ponnuru has suggested expansion of the child tax credit and reduction of payroll taxes.

As Ryan has argued in speeches, the purpose of the GOP should not be to simply balance budgets or win elections, but to help people.

The GOP is certainly not dead yet. It could well capture the Senate in 2014 and control Congress until 2016. But unless a Republican version of the DLC succeeds in countering Limbaugh and the tea party, it’s as doomed as the Democrats were for 20 years.