It’s CPAC weekend — the grand rallying of the conservative clan here in Washington. It’s a season where conservatives from across the country meet to compare notes, share stories, and seek political consensus. The consensus forming this year however is an ominously dangerous one — ominously dangerous to conservatives themselves that is.

Conservatives live in thrall to a historical myth, and this myth may soon cost us dearly.

The myth is the myth of the Goldwater triumph of 1964. It goes approximately as follows:

In 1964, after years of watered down politics, Republicans turned to a true conservative, Arizona Senator Barry Goldwater. Yes, Goldwater lost badly. But in losing, he bequeathed conservatives a national organization — and a new champion, Ronald Reagan. Goldwater’s defeat opened the way to Reagan’s ultimate triumph and the conservative ascendancy of the 1980s and 1990s.

This (the myth continues) is the history we need to repeat. If we can just find the right messenger in 2012, the message that worked for Reagan will work again. And even if we cannot find the right messenger, losing on principle in 2012 will open the way to a more glorious victory in 2016.

The Goldwater myth shuts down all attempts to reform and renew our conservative message for modern times. And it offers a handy justification for nominating a 2012 presidential candidate who might otherwise seem disastrously unelectable. Altogether, the myth invites dangerous and self-destructive behavior by a party that cannot afford either.

What happened in 1964 was an unredeemed and unmitigated catastrophe for Republicans and conservatives. The success that followed 16 years later was a matter of happenstance, not of strategy. That’s the real lesson of 1964, and it is the lesson that conservatives need most to take to heart today.

1964 was always bound to be a Democratic year. The difference between Barry Goldwater’s 38.5% candidacy and the 44% or 45% that might have been won by a Nelson Rockefeller or a William Scranton was the effect on down-ballot races.

Republicans lost 36 seats in the House of Representatives in 1964, giving Democrats the biggest majority in the House any party has enjoyed since the end of World War II. Republicans dropped 2 seats in the Senate, yielding a Democratic majority of 68-32, again the most lopsided standing in any election from the war to the present day.

This huge congressional majority — call it the Goldwater majority — liberated President Johnson from any dependence on conservative southern Democrats. In 1964, only 46 Senate Democrats voted for the great Civil Rights Act; 21 opposed. Without Republican support, the Act would not have passed. (And indeed while 68% of Senate Democrats voted for the Act, 81% of Senate Republicans did.)

While dependent on southern Democrats, President Johnson had to develop a careful, pragmatic domestic agenda that balanced zigs to the right (in 1964, Congress passed the first across the board income tax cut since the 1920s) with zags to the left (the Economic Opportunity Act of 1964 which created Head Start among other less successful programs).

Then came the Republican debacle of November 1964. Goldwater’s overwhelming defeat invited a tsunami of liberal activism. The 89th Congress elected in 1964 enacted both Medicaid and Medicare. It passed a new immigration law, opening the way to a surge of 40 million newcomers, the overwhelming majority of them from poor Third World countries. It dramatically expanded welfare eligibility and other anti-poverty programs that together transformed the urban poor of the 1950s into the urban underclass of the 1970s and 1980s.

Suppose history had taken a different bounce in 1964. Suppose somebody other than Sen. Goldwater had won the Republican presidential nomination. Suppose his narrower margin of defeat had preserved those 36 Republican seats in the House — or even possibly gained some seats. (The big Democratic gains in 1958 and 1962 were ripe for a rollback in 1964 — and indeed were rolled back in 1966, when the GOP picked up 47 seats in the House and 3 in the Senate.)

Under those circumstances, the legislation of 1965 might have looked a lot more like the more moderate legislation of 1964. The Voting Rights Act would surely have passed, and so too would some form of health insurance measure for the poor — a measure supported by the American Medical Association and health insurers as well as by congressional liberals. But Medicare might never have happened, or might have taken a less costly form. The immigration bill might have been more carefully written so as to achieve its declared purpose: eliminating racial discrimination in immigration without expanding the overall number of immigrants from the modest level prevailing in the 1950s and early 1960s.

True, the liberal triumph of 1964 set in motion the train of disasters that laid liberalism low in the 1980s. But those disasters followed from choices and decisions that liberals made — not from some multiyear conservative grand strategy for success in 1980. It was not Goldwater who made Reagan possible. It was Carter. Had Carter governed more successfully, the Goldwater disaster would have been just a disaster, with no silver lining. And there was nothing about the Goldwater disaster that made the Carter failure more necessary, more inevitable.

And anyway, as the years pass, the consequences of Reagan’s victory look more temporary and provisional, at least in domestic policy — while the consequences of Goldwater’s defeat look more enduring and more consequential. The Reagan tax cuts are long gone. Medicare is still here.

It’s important for Republicans to absorb and remember this history as they prepare to make their next political choices. Right now, Republicans are gripped by a strong martyr complex. They want to stand up for their beliefs, damn the consequences — in fact the worse the consequences, the more it proves the rightness of our beliefs. If this mood persists further into the 2012 cycle, we will pay a heavy price. 2010 is already shaping up as an inhospitable year for Republicans, especially in the Senate, where the map favors the Democrats. 2012 could be much better — unless we doom ourselves by our own bad choices.

It is this alternative possibility of success or failure down the ballot as well as up that makes it so urgent to disenthrall ourselves of the 1964 myth. Goldwater’s defeat was a prelude to nothing except defeats on the floor of Congress in 1965-66. As the next presidential cycle begins, our priority should be to identify presidential candidates who can run strongly in every region of the country — not because we expect to win every region of the country, but because we want to help elect Republican congressional candidates in every region of the country. Our present strategy is one that is paving the way not merely to another defeat at the presidential level, but to a further shriveling of our congressional party — and an utterly unconstrained Obama second term that will make LBJ’s ascendancy look moderate and humble in comparison.