Opinion: Happy anniversary! It’s been almost two years since Donald Trump began lying from the Oval Office

It’s been almost two years since Donald J. Trump took the oath of office and began producing a remarkable string of lies, half-truths and insults.

So it’s interesting that Sunday, we can mark the halfway point of his first term — and rest assured this country is perfectly capable of electing him to a second one — by seeing the liar-in-chief accuse his former lawyer, who has indeed confessed to lying before, of lying again.

Oddly, the lawyer, Michael Cohen, gets more of the benefit of the doubt than does the president, if for no other reason than Cohen has at least admitted to the obvious.

The president, on the other hand, is incapable of acknowledging a falsehood, even one that might have arisen from honest error.

I’ve written before about the corrosive effects of Trump’s constant lies and half-truths on our democracy. The Washington Post’s running tally, last updated at the end of December, counted 7,645 false or misleading claims by the president over the course of his first 710 days in office. That’s an average of nearly 11 lies or half-truths a day.

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The Times’s White House reporter, Noah Bierman, writes about how Trump’s fundamental unreliability has made him possibly the worst dealmaker in Washington, a city of dealmakers.

When your word is worthless, people don’t trust you. And when people don’t trust you, you wind up spending a lot of time alone in the Oval Office tweeting madness to the world.

So what can we expect for the next two years?

More of the same, and likely worse. If Republican friends such as Senate Majority Leader Mitch McConnell of Kentucky, who shares much of Trump’s smaller-government agenda, can’t trust him as a reliable ally, then House Speaker Nancy Pelosi (D-San Francisco) certainly can’t, either. Which means Trump has painted himself into a bargaining corner.

And that just adds more rust to the wheels of governance.