First, Will quotes Warren:
There is nobody in this country who got rich on his own. Nobody. You built a factory out there — good for you. But I want to be clear. You moved your goods to market on the roads the rest of us paid for. You hired workers the rest of us paid to educate. You were safe in your factory because of police forces and fire forces that the rest of us paid for. . . . You built a factory and it turned into something terrific or a great idea — God bless, keep a big hunk of it. But part of the underlying social contract is you take a hunk of that and pay forward for the next kid who comes along.
The part he leaves out doesn't really change her meaning of his reading of her meaning. Here it is: "You didn't have to worry that marauding bands would come and seize everything at your factory, and hire someone to protect against this, because of the work the rest of us did."
Will goes on to claim that Warren is critiquing a rhetorical straw man. "She refutes propositions no one asserts," he writes. He then goes on to refute what he takes to be her propositions.
Everyone knows that all striving occurs in a social context, so all attainments are conditioned by their context. This does not, however, entail a collectivist political agenda. Such an agenda’s premise is that individualism is a chimera, that any individual’s achievements should be considered entirely derivative from society, so the achievements need not be treated as belonging to the individual. Society is entitled to socialize — i.e., conscript — whatever portion it considers its share. It may, as an optional act of political grace, allow the individual the remainder of what is misleadingly called the individual’s possession.
Speaking of straw men -- or women -- Warren at no point in the previous quote proposes that society "conscript" a socially-determined portion of any individual's achievements. If anything, Warren appears to be asserting a moral imperative that follows from the presumption of a social contract. Will moves on from here to a broader attack on liberalism that goes beyond the scope of Warren's remarks -- for him, liberalism assumes individuals' inability to think for themselves amid an onslaught of advertising and PR and assigns an enlightened political class to act as guardians for the rest of us. Will easily refutes this notion by noting all the times that PR manipulation has failed, from car advertising to massive campaign spending, but that's a refutation of liberalism or progressivism only if you accept Will's own straw-man definition of the idea.
We can leave the rest of Will's column behind, because his specific engagement with Warren gets to the real heart of the matter. The question raised between them is: what follows from interdependence? Warren suggests that interdependence obliges individuals in a matter not entirely countenanced by individualist dogma. Will insists that there is some indeterminate yet irreducibly individual initiative in possibly every collective endeavor that entitles the decisive individual to the share of the achievement that he or she, not society, deems appropriate. In simplest terms, achievements depend on ideas and ideas only come from individuals. Therefore justice entitles individuals to the first fruits of their ideas. Those whose efforts are essential to the realization of the idea still must realize that the idea alone enabled them to achieve. An appreciation of their dependence on the idea should result in a glad concession to the idea-maker of discretion in the distribution of the fruits of the idea. For Will, individualism is actually an ideology of hierarchy and leadership; it requires recognition that some individuals will inevitably lead the rest for the collective good (in Will's Hayekian terms, "spontaneous order") and prosper more as a result. I don't know if Elizabeth Warren would actually challenge as many of these premises as others would, but she at least raises the basic question: what follows from interdependence? Will answers by implying that there is never really interdependence, but always dependence of the many upon the initiative of the one or the few. That implication doesn't disprove the assertion that interdependence comes with mutual obligations that override individualist ideology. But Will does claim that interdependence does not impose compromising obligations on individualists. The argument is dishonest on a level he may not appreciate, and the ultimate question remains open for the rest of us.