Washington ? Outside the venue where Rep. Paul Ryan recently spoke in Madison, Wis., a university town never lacking protesters, one product of America’s education system shouted that Ryan’s budget proposal would return America to the bad old days of the “18th-century robber barons.” The young man, full of zeal and destitute of information, does not know that those capitalists of whom he disapproves — the ones who built the railroads and other sinews of the nation’s industrial might — operated in the second half of the 19th century, not in 18th-century agrarian America.

Last month, Barack Obama was asked by an interviewer from Texas why he is so unpopular there. Obama replied: “Texas has always been a pretty Republican state, for, you know, historic reasons.” Well, yes, “always” — if you believe, as many baby boomers seem to, that the world began when they became more or less sentient. But, for the record:

Texas, one of the 11 states of the Confederacy, was, for historic reasons, part of the solidly Democratic South for almost a century after the Civil War. Deeply Protestant Texas voted for Republican Herbert Hoover against Al Smith, a Catholic New Yorker, for president in 1928, but it did not vote for a Republican presidential candidate again until Dwight Eisenhower carried the state in 1952 and 1956. It did not do so again until Richard Nixon in 1972.

Four years later, it embraced Jimmy Carter. Other than during Reconstruction, Texas did not elect a Republican senator until 1961 (John Tower) and did not elect a second one (Phil Gramm) until 1984, and there were not as many as three Texas Republicans in the U.S. House until 1968. Republicans were not a majority of the state’s congressional delegation until 2005.

Responding to Ryan’s budget proposal, Obama said it “would lead to a fundamentally different America than the one we’ve known certainly in my lifetime. In fact, I think it would be fundamentally different than what we’ve known throughout our history.”

Well. It is unclear what “fundamentally” means to Obama, but consider some possible metrics of what is, and is not, different than what we have known “throughout our history.” Ryan’s plan would reduce federal spending as a percentage of GDP from the 2009-11 average of 24.4 to 19.9 in 10 years. It was not until the nation was 158 years old — in the Depression year of 1934, with the New Deal erupting — that peacetime federal spending topped 10 percent of GDP, and it did not reach 12 percent until the war preparations of 1941.

Ryan’s plan would alter Medicare. But Medicare has existed in its current configuration for only 46 of the nation’s 235 years.

Ryan’s plan would involve some seniors paying more of the costs of routine health care. But what is anomalous, viewed in the context of “our history,” is today’s “12 cents” problem. That is the portion of every health dollar paid by the person receiving the care. Fifty years ago, when John Kennedy became president and the nation was 185 years old, the figure was 47 cents.

Ryan’s plan would expand states’ discretion in the administration of Medicaid by making it a block grant program. Would it make America, in Obama’s words, “fundamentally different than what we’ve known throughout our history” to take this small step away from the practice of reducing states to administrative extensions of the federal government?

The hysteria and hyperbole about Ryan’s plan arise, in part, from a poverty of today’s liberal imagination, an inability to think beyond the straight-line continuation of programs from the second and third quarters of the last century. It is odd that “progressives,” as liberals now wish to be called, have such a constricted notion of the possibilities of progress.

Liberals think Medicare and Social Security as they exist are “fundamental” to the nation’s identity. But liberals think the Constitution — which the Framers meant to be fundamental, meaning constituting, law — should be construed as a “living” document, continually evolving to take different meanings under whatever liberals consider new social imperatives.

The lesson of all this is that one’s sense of possibilities — and proprieties — is shaped by what we know, and often do not know, about history. The regnant ideology within the Obama administration and among congressional Democrats is reactionary liberalism, the conviction that whatever government programs exist should forever exist because they always have existed. That is, as baby boomers, in their narcissism — or perhaps solipsism; or both — understand “always.”