Whose budget is 'antithetical' to American history?

In critiquing Republican Paul Ryan's budget proposal, President Obama characterized House Budget Committee Chairman's cost-cutting measures as "thinly veiled social Darwinism" that is "antithetical to our entire history."

First of all, Ryan's budget proposes to keep the size and scope of the federal government substantially larger than it was under Bill Clinton. Does that make Clinton a "social Darwinist"?

Cato's David Boaz further examines Obama's "social Darwinist" smear:

Is “social Darwinist” within some bound of propriety that “socialist” violates? ...

Those who deploy the charge are, first, falsely implying that Republicans support radically smaller government, which neither Ryan’s budget nor any other Republican plan actually proposes. And second, they are accusing both Republicans and actual supporters of free markets of believing in “the survival of the fittest” and, as Wikipedia puts it, “the ideas of eugenics, scientific racism, imperialism, fascism, Nazism and struggle between national or racial groups.”  “Social Darwinism” is nothing more than a nasty smear.

The president should be embarrassed, and those who call for civility in public discourse should admonish him.

But nevertheless, Obama is sticking by the charge.  "I am not exaggerating," the president said. "These are facts."

Really? Let's examine these "facts."  How exactly does President Obama fare in the context of history?  Washington Examiner's Con Carroll explains:

According to the Historical Tables produced by the White House Office of Management and Budget, spending as a percentage of gross domestic product under President Clinton (1993-2000) averaged 19.8 percent and never went above 21.4 percent in 1993. Under President Bush (2001-2008) it averaged 19.6 percent and never went above 20.8 percent. In fact, since demobilization after World War II (1947-2011), spending as a percentage of gdp has averaged 19.7 percent and reached a record 25.2 percent in 2009.

Now compare Obama and Ryan's federal spending plans as a percentage of GDP:

As evidenced by this chart, Obama's plan for federal spending levels stays far above the post-World War II average.  But in contrast, the Ryan budget cuts spending by an average of 20% of GDP over a 10-year span.

So whose budget is actually "antithetical" to U.S. history?

As the Heritage Foundation points out, Paul Ryan's budget plan is much more in line with America's traditional (and historical) values than any plan coming out of the Obama White House:

This is really about two visions for the future of the country. Under one, we follow in the footsteps of Greece and Italy, replete with debt crises and an economic and cultural meltdown and in the end, vastly higher taxes. Under another, we return to our smaller government roots with lower spending and lower taxation—for all Americans—and unshackle our system of free enterprise so Americans from all walks of life can seize opportunity.