Are conservatives ever right?

The question isn’t meant to suggest that liberals are never wrong. But reviewing the last few decades of conservative policy initiatives—or their objections over that timespan to policies they hate—shows a consistent pattern of failure: predictions never pan out, and intended results turn to catastrophic flops.

Given the G.O.P.’s midterm victories this week, the question is of particular import. Come January, conservatives will have control of both houses of Congress, and hold a considerable legislative advantage in the last two years of the Obama presidency. Yet not a week ago, conservative politicians and commentators were screaming out batty ideas as they demanded that President Obama close the borders over Ebola, ignoring the advice of infectious disease specialists who know that shutting borders against a disease leads people to make travel by means that aren’t easily tracked, escalates danger, and harms the ability to stop the infection at its source. Conservative know-nothings dismiss the professionals as know-nothings themselves, despite their training and expertise.

And that could be the problem. Too often, it seems, conservatives have scorned experts as incompetent, biased, or otherwise worth ignoring because they came up with answers that didn’t fit their politically desired answer. Often, they proclaim experts have a liberal bias. Of course, plenty of Democrats have voted for conservative ideas, but that is beside the point. The question is whether policies proposed by conservatives failed, not whether they were passed into law. And this question is all the more important now, with the Republicans having re-captured control of the Senate. Will they govern based on a knowledge of history and the analysis of experts? Or will they resort to faith-based, sure-we’re-right policies—like trying to impose a border ban to stop Ebola—that may lead the ignorant to cheer but will leave turn the experts’ hair white with fear.

Before venturing through the rogues’ gallery of past disasters, an exception that proves the rule: the 1983 decision by the Reagan Administration to deploy missiles in Europe to counter Russian SS-20s was a success, ultimately contributing to the Soviet collapse. But otherwise, there is not a lot in the last three decades to give conservatives bragging rights, and with almost every fiasco, they blame someone else. So let’s look at the record of the last 30-some years:

Tax cuts pay for themselves.

The fantasy: In 1981, as he championed massive tax cuts, President Ronald Reagan promised there would be no growth in the federal budget deficit because the economic boom that would follow would lead to higher revenues.

Reality: Budgeted federal revenues dropped, leading to a huge fiscal hole. Deficits rose to 6 percent of G.D.P. by 1983, then the highest in peacetime history. Reagan tacitly admitted failure by reversing directions and raising taxes multiple times, starting in 1982.

Blame: Conservatives claimed Democrats in Congress ran up spending so much that the growth of revenues could not keep up with the growth in outlays.

The excuse is false: According to a 2002 report prepared by the House and Senate Appropriations Committees, when all appropriations bills during the Reagan administration are taken into account, the big spender was Reagan himself. All told, the report shows, Reagan requested about $4.7 trillion in his budgets submitted to Congress—including the regular annual budget, the supplementals and deficiency appropriations. In the final action, Congress spent a bit less than that amount. (I know, Republicans’ heads just exploded. Read the official report.)

The Aftermath: History is ignored. Conservatives still insist, on no evidence, that cuts pay for themselves. Trillions of dollars in debt have been run up over 30 years because of tax cuts. Republicans in Congress have introduced legislation that would force the Congressional Budget Office to change how it calculates projected losses from tax cuts to make future results align more closely to conservative predictions.