Unlike Bush, though, Clinton doesn’t want for federal-bureaucratic experience, and unlike Obama, she doesn’t want for relationships in Congress. Kaine’s expertise and Clinton’s are somewhat redundant. What Clinton does lack is media savvy and universal faith among the Democratic base in her judgment. Warren epitomizes both of those qualities.
Kaine is generally presumed to be better qualified for the presidency than Warren, but this is a bit like arguing only one angel can dance on the head of a pin. Warren and Kaine entered the Senate at the same time. And while Kaine governed Virginia for four term-limited years, Warren worked in the federal government for a year as an adviser to Obama and Treasury Secretary Timothy Geithner, tasked with standing up the Consumer Financial Protection Bureau (an agency that was her intellectual brainchild). She proved to be an able bureaucrat and savvy operator in that role, and used the experience to build a foundation for her successful Senate candidacy.
What Warren lacks relative to Kaine in executive experience she makes up for with a clear, consistent, and progressive ideology. President Kaine would likely be a fine president, perhaps a great one, but his slate is much blanker than Warren’s. Democrats at the elite and grassroots level know what Warren’s substantive goals are, and have responded to them enthusiastically.
The fact that Warren really is better than anyone other than perhaps Barack Obama at getting under Trump’s skin is an added bonus, but an important one.