Donald Trump still refuses to say whether he will concede the presidential election if he loses. As many people have explained, this is dangerous; it undermines the trust that our democratic system of governance relies on and could lead to voter intimidation on Election Day.

It’s also unprecedented in modern history. In fact, presidential candidates can be very gracious in their defeat. Exhibit A: George H.W. Bush’s letter conceding the Oval Office to Bill Clinton after Bush lost his reelection campaign:

Read this. Think about this. George H.W. Bush's gracious handoff to Bill Clinton. It's beautiful. pic.twitter.com/XHjPvbzGu8 — Tom Ashbrook (@tomashbrooknpr) October 19, 2016

In case you can’t read that, here’s what it says:

Dear Bill, When I walked into this office just now I felt the same sense of wonder and respect that I felt four years ago. I know you will feel that, too. I wish you great happiness here. I never felt the loneliness some Presidents have described. There will be very tough times, made even more difficult by criticism you may not think is fair. I’m not a very good one to give advice; but just don’t let the critics discourage you or push you off course. You will be our President when you read this note. I wish you well. I wish your family well. Your success is now our country’s success. I am rooting for you. Good luck, George

This is how the election is supposed to work. But Trump seems ready to break yet another norm of basic decency in our political system.

Watch: This election isn’t just Democrat vs. Republican. It’s normal vs. abnormal.