President Trump is endorsing candidates in a series of primary elections this month, trying to defeat incumbents in his own party who have crossed him. Our national political correspondent Shane Goldmacher explains.

The historian Helena Rosenblatt traces the roots of liberalism and the values that many have forgotten.

Ohio’s unusual contest — with a little-known incumbent and a well-known challenger — shows how Democrats are hoping to capitalize on G.O.P. voters’ anger at the Jeffrey Epstein scandal.