This week the Republican senators Tom Cotton of Arkansas and David Perdue of Georgia introduced a bill that they said would cut legal immigration to the United States by 50 percent. They are right about that, but nearly everything else that they have said about their bill is false or misleading.

The senators, whose bill is endorsed by President Trump, argue that America is experiencing abnormally high immigration; that these immigrants are hurting American wages; and that their bill would prioritize skilled immigrants, the way Canada does, thus making the United States more competitive internationally. These talking points are pure fiction.

They have justified this drastic cut in immigration by stating that the bill will, as they put it in February when announcing an earlier version, bring “legal immigration levels” back down to “their historical norms.” But the senators fail to consider the impact of population growth. A million immigrants to the United States in 2017 isn’t equivalent to the same number in 1900, when there were a quarter as many Americans.

Controlling for population, today’s immigration rate is nearly 30 percent below its historical average. If their bill becomes law, the rate would fall to about 60 percent below average. With few exceptions, the only years with such a low immigration rate were during the world wars and the Great Depression. Surely, these are not the “norms” to which the senators seek to return.