So far as the impact on the election is concerned, Mr. Trump was already projected to be leading Mr. Biden narrowly in swing States — critical to the election result — in a range of polls. Now, that lead may widen, although whether it will be unassailable by election day remains to be seen. The ratings of former President Ronald Reagan jumped dramatically after he was shot by a man on March 30, 1981, 69 days after assuming office, yet that boost disappeared within several weeks. The more complex and troubling question is the extent to which the Trump campaign, in its bid to capitalise on the near martyrdom of its candidate, will adopt the language of hate politics, building on vicious comments that have already been circulating on social media since the attack, many of them blaming Democrats for the violence and deliberately conflating political opposition with personal animus. If the two presidential candidates, their campaign teams, and their party leaders abandon common civility in what should ideally be a structured partisan contest and allow baser populist instincts to dominate their speeches in the months ahead, it will inevitably exacerbate the already bitter state of polarisation in the public discourse. Whoever wins on November 5 would then stand on the brink of a deeply troubled polity, hardly the ideal scenario to build bipartisan bridges, so essential to ensure that the U.S. can tackle the many challenges it faces, foreign and domestic.