Four years ago, Barack Obama was America's Rorschach test upon whom voters could project their disparate yearnings. To govern, however, is to choose, and now his choices have clarified him. He is a conviction politician determined to complete the progressive project of emancipating government from the Founders' constraining premises, a project Woodrow Wilson embarked on 100 Novembers ago.

As such, Obama has earned what he now receives, the tribute of a serious intellectual exegesis by a distinguished political philosopher. In “I Am the Change: Barack Obama and the Crisis of Liberalism,” Charles Kesler of Claremont McKenna College rightly says Obama is “playing a long, high-stakes game.” Concerning the stakes, Obama practices prudent reticence, not specifying America's displeasing features that are fundamental. Shortly before the 2008 election, he said only: “We are five days away from fundamentally transforming” America. Tonight, consider Obama's acceptance speech in the context that Kesler gives it in the American political tradition.

Progress, as progressives understand it, means advancing away from, up from, something. But from what?

From the Constitution's constricting anachronisms. In 1912, Wilson said, “The history of liberty is the history of the limitation of governmental power.” But as Kesler notes, Wilson never said the future of liberty consisted of such limitation.

Instead, he said, “every means ... by which society may be perfected through the instrumentality of government” should be used so that “individual rights can be fitly adjusted and harmonized with public duties.” Rights “adjusted and harmonized” by government necessarily are defined and apportioned by it. Wilson, the first transformative progressive, called this the “New Freedom.” The old kind was the Founders' kind — government existing to “secure” natural rights (see the Declaration) that pre-exist government. Wilson thought this had become an impediment to progress. The pedigree of Obama's thought runs straight to Wilson.

And through the second transformative progressive, Franklin Roosevelt, who counseled against the Founders' sober practicality and fear of government power: “We are beginning to wipe out the line that divides the practical from the ideal” and are making government “an instrument of unimagined power” for social improvement. The only thing we have to fear is fear of a government of unimagined power:

“Government is a relation of give and take.” The “rulers” — FDR's word — take power from the people, who in turn are given “certain rights.”

This, says Kesler, is “the First Law of Big Government: the more power we give the government, the more rights it will give us.” It also is the ultimate American radicalism, striking at the roots of the American regime, the doctrine of natural rights. Remember this when next — perhaps tonight — Obama discourses on the radicalism of Paul Ryan.

As Kesler says, the logic of progressivism is: “Since our rights are dependent on government, why shouldn't we be?” This is the real meaning of Obama's most characteristic rhetorical trope, his incessant warning that Americans should be terrified of being “on your own.”

Obama, the fourth transformative progressive, had a chief of staff who said “you never want a serious crisis to go to waste.” More than a century before that, a man who would become the first such progressive said a crisis is a terrible thing not to create. Crises, said Wilson, are periods of “unusual opportunity” for gaining “a controlling and guiding influence.” So, he said, leaders should maintain a crisis atmosphere “at all times.”

Campaigning in 1964, Lyndon Johnson, the third consequential progressive, exclaimed through a bull horn: “I just want to tell you this — we're in favor of a lot of things and we're against mighty few.” He learned this progressive vernacular from his patron, FDR, who envisioned “an unlimited civilization capable of infinite progress.” Poet Archibald MacLeish, FDR's choice for librarian of Congress, exemplified progressives' autointoxication: America has “the abundant means” to create “whatever world we have the courage to desire,” and the ability to “take this country down” and “build it again as we please,” to “take our cities apart and put them together,” to lead our “rivers where we please to lead them,” etc.

In 2012, Americans want from government not such flights of fancy but sobriety; not ecstatic evocations of dreamlike tomorrows but a tolerably functioning today; not fantasies about a world without scarcities and therefore without choices among our desires and appetites but a mature understanding of the limits to government's proper scope and actual competence. Tonight's speech is Obama's last chance to take a first step toward accommodation with a country increasingly concerned about his unmasked determination to “transform” what the Founders considered “fundamentals.”

George Will's email address is georgewill@washpost.com.