It’s true that the ruble has plummeted against the dollar this month, falling about 8 percent. But that isn’t because the Russian government is playing some devaluation game. The ruble fell because stringent new sanctions on influential Russians are crimping demand for the currency.

China and the ‘Currency Devaluation Game’

In the case of China, the accusation is outdated. China has allowed the value of its currency to rise in the last year — to 6.3 yuan to the dollar from 6.9 yuan to the dollar last April. That is the opposite of a currency devaluation game.

But the president’s statement has greater validity if you look over a longer period. China has used management of its currency to shape its economy. A decade ago, it was doing exactly what the president suggests — pushing the value of the yuan downward to give an advantage to Chinese exporters.

That was implicitly acknowledged in a Treasury Department report last week that declined to name China a “currency manipulator,” as Mr. Trump often argued it was on the campaign trail. That report listed China along with Japan, South Korea, Taiwan, Germany and Switzerland as countries the United States is monitoring for their currency practices.

“China has a long track record of engaging in persistent, large-scale, one-way foreign exchange intervention, doing so for roughly a decade to resist” currency appreciation, the report said.