His refusal to debate, even on the friendly territory of Fox News, suggests he is unwilling to risk the unpredictability of a head-to-head contest with the vice president in the final weeks of the campaign. Harris has said she’s open to another matchup. Trump’s social media post came hours after Fox proposed a debate in Pennsylvania later this month. Harris accepted a second debate following their first showdown hosted by ABC on Sept. 10, saying the candidates “owe it to the voters” to have a...