President Trump’s Twitter attacks on the late Sen. John McCain, R-Ariz., over the weekend — including his retweet of one supporter who explained that she “hated” the late senator — invite the question: Why does Trump harbor such a special hatred for the long-deceased McCain?

Well, Trump would suggest it’s three factors. First, there’s McCain’s transmission of the so-called Steele dossier to the FBI. Compiled by Christopher Steele, the former British intelligence officer, that dossier suggested Trump’s involvement in various nefarious and lewd activities. Then there’s McCain’s decision to vote down the health care bill sponsored by his friend Sen. Lindsey Graham, R-S.C. That bill, which would have passed had McCain supported it, would have replaced the Affordable Care Act, also known as Obamacare. Finally, there’s McCain’s sustained criticisms of Trump during the first 18 months of his presidency.