We’re in the middle of the worst economic disaster in modern history and we’re doing almost nothing about it, warns UC Berkeley Economist J. Bradford DeLong.

“So unless something — and it will need to be something major — returns the U.S. to its pre-2008 growth trajectory, future economic historians will not regard the Great Depression as the worst business-cycle disaster of the industrial age,” he writes. “It is we who are living in their worst case.”

The former Clinton administration official wonders why a disaster that “robs the average American family of four of $36,000 per year in useful goods and services, and that threatens to keep Americans poorer than they might have been for decades,” isn’t motivating policymakers to act.

“One would think that America’s leaders would be clambering to formulate policies aimed at returning the economy to its pre-2008 growth path: putting people back to work, cleaning up underwater mortgages, restoring financial markets’ risk-bearing capacity, and boosting investment,” he says.

Instead, Congress is debating about how much our investments should be reduced, how few weeks we should help the unemployed, how much food stamps should be cut.

The reason why we aren’t acting is clear to DeLong: “…at the top, there is no crisis.” While the incomes of the bottom 90 percent have stagnated for decades, the top has flourished. “The incomes of America’s top 10 percent are two-thirds higher than those of their counterparts 20 years ago, while the incomes of the top 1 percent have more than doubled,” he writes.

This inequality isn’t an accident of history or the result of rapid technological advancement, as conservatives like to pretend.

It’s the result of the class war the right has been waging for decades.

“Among developed countries, the U.S. does have the most unequal distribution of disposable income after taxes and transfer payments,” writes economist Laura Tyson, former chair of the President’s Council of Economic Advisers.

Our tax system is more progressive than most European countries that rely on a value-added tax but we spend far less on programs that help families and keep inequality low.

This is the victory of a conservative movement that caters to the richest Americans and seems to have no problem with a recovery that is only benefiting the richest 10 percent. Actually, it seeks to maintain the advantage for the richest by opposing policies like Medicaid expansion and assailing the labor movement.

The Republican Party doesn’t even feel the need to bother with solutions to problems that plague the lower 90 percent, like unemployment, says New York magazine’s Jonathan Chait.

“Republican thought on mass unemployment is a restaurant with tiny portions that taste terrible,” he writes.

The problem for the left is that Republicans can run and win on policies that directly increase income inequality. They can resist Democratic initiatives — even wildly popular ideas like raising the minimum wage, which would reduce poverty and increase consumer spending — and still be on track to hold the House of Representatives, while possibly even wining the Senate.

Why doesn’t the Republican Party act to reverse the greatest economic disaster in at least half a century, a disaster they could prevent?

Rep. Paul Ryan (R-WI) can reveal his secret passion for alleviating poverty over and over again while promoting policies that increase it. And still be taken seriously.

Republicans don’t care about improving the economy for the bottom 90 percent for one simple reason.

They don’t have to.