Donald Trump’s paltry crowd for his weekend campaign rally in Oklahoma raises new questions about politics in the age of coronavirus: Maybe pandemic-scarred Americans just aren’t ready to risk exposure for close-up engagement in the 2020 presidential election.Only about a third of seats in the 19,000-seat BOK Center were filled for the rally, despite boasts by Trump and his campaign team that they had received more than 1 million ticket requests.With all 50 states well into reopening their economies, Americans are now creating their own individual risk budgets and calculating what sort of activities are worth hazarding when coronavirus infections are still surging in some areas of the country.