President Donald Trump’s campaign is struggling to define Sen. Kamala Harris. Joe Biden’s decision to choose Harris as his running mate has complicated the Trump campaign’s crude efforts to paint Biden as out of step with the country. Less than 90 days out from Election Day, Trump’s team faces a pivotal choice in how it tries to define the Democratic ticket. Do they attempt to fire up their base and scare off moderates by painting Biden and Harris as radical socialists? Or do they aim to depress enthusiasm among Democrats by arguing Biden and Harris are opportunistic and insufficiently liberal?