“Never let a serious crisis go to waste,” Rahm Emanuel remarked last fall. But in a crisis, all the public tends to care about are jobs and economic growth. It’s not the ideal time to pass costly social legislation that promises to reap dividends only in the long term, if at all.

That’s why Franklin Roosevelt waited until 1935, when the Great Depression seemed to be waning, to push Social Security through Congress. It’s why Lyndon Johnson established Medicare at the peak of the long post-World War II expansion. And it’s why Massachusetts’s health care plan and California’s cap on greenhouse-gas emissions both passed at the height of the recent boom, rather than the bottom.

Obama is still broadly popular, and the public is still broadly sympathetic to his administration’s agenda. But the money has to come from somewhere. You can’t have a bold new liberal era without the growth to pay for it.

The president wants to govern America like a blue state. But for that to work, he’ll need the nation’s economy to start performing more like Texas.