Biden v. Trump: The battle over who’s too old, too forgetful or too confused

And Trump’s own last GOP rival, former U.N. Ambassador Nikki Haley, has made both Biden’s and Trump’s age an issue, renewing her calls for mandatory cognitive tests for politicians over the age of 75.

Unlike in years past, when propriety dictated treading cautiously around the issue, now campaigns are going to age immediately — and more explicitly than ever before. The emerging front in the presidential campaign is not an argument…