The coronavirus pandemic has upended the 2020 presidential campaign. Rallies have been canceled, primaries are being delayed, and even where voting is taking place on schedule, canvassing and other normal politicking is on hold as voters increasingly shelter in place. Slowing the spread of the virus has taken precedence over getting the message out, forcing the candidates off the trail.President Trump, however, is just as visible as ever. While former Vice President Joe Biden and Sen. Bernie Sanders have been relegated to the sidelines, Trump has been a fixture of the White House’s daily press briefings on the coronavirus. While the setting and subject matter are vastly different than his freewheeling “Make America Great Again” rallies, Trump still manages to get in his trademark flourishes. There are the jokes (Trump pretended to flee when coronavirus point woman Deborah Birx acknowledged feeling ill over the weekend), the shots at political rivals in the Democratic Party (“I was called ‘xenophobic’ by Sleepy Joe Biden”) and his own (“Romney is in isolation? Gee, that’s too bad”), and, of course, sparring with the media (“I say that you’re a terrible reporter”).And according to the polling data, the new dynamic is not only hamstringing Trump's rivals but boosting the president's own standing behind the podium. After initially giving Trump relatively low marks, Morning Consult recorded a nearly 10-point jump in approval of his handling of the coronavirus in a week’s...