Michael Barone's point is a strong one: the results in Pennsylvania mean that Hillary Clinton can absolutely win the popular vote.
Even so, Clinton now leads in the popular vote, if you include the Florida and Michigan results, by 121,943 votes. And even if you include the imputed totals for the Iowa, Nevada, Washington, and Maine caucuses, she's ahead by 11,721 votes. It seems to me that this provides the Clinton campaign with an important talking point, though one they're probably reluctant to use over the next two weeks. Reluctant, because the likely Obama victory in North Carolina could erase this popular-vote lead, and) an offsetting Clinton margin in Indiana seems unlikely (or at least risky to project from current polling). But looking ahead from May 6, Clinton is likely to regain that popular-vote lead (including Florida and Michigan) and quite possibly could gain a popular-vote lead counting just Florida and not the more problematic (because Obama was not on the ballot there) Michigan. She'll get big margins in West Virginia on May 13 and Kentucky on May 20, and it's not clear Obama will get a big margin in Oregon on May 20; Obama won the nonbinding February 19 primary in Washington only narrowly. If Clinton wins big in Puerto Rico on June 1, as the one poll I've seen there suggests, that will far outshadow in popular votes any Obama margins in South Dakota and Montana on June 3.