Stopping "illegal," or, more appropriately, undocumented immigration was one of the big three messages of Donald Trump's presidential campaign.

But so was stopping legal immigration, and now Trump's fellow Republicans are making good on his promises.

On Tuesday, two leading Republican senators -- Georgia Senator David Perdue and Arkansas Senator Tom Cotton -- introduced a bill that they say would cut legal immigration to the United States by a whopping half.

It would do this by limiting green cards, slashing away at the number of refugees that are legally allowed to flee to America, and ending a lottery system that brings in immigrants from countries under-represented in the country as a whole.

Cotton defended the plan Tuesday night on Fox So-Called News - saying it was all about defending "blue-collar workers"

Cotton is a smart politician who knows how to say the right things to make Fox happy - but he's not telling the truth about this.

His bill isn't about protecting workers and raising wages, it's about something else -- something so ugly that Cotton wouldn't even say on Fox So-Called News.

It's about "Making America White Again."

Think of it this way.

If Cotton and Perdue really cared about wages and workers - they'd raise the minimum wage so that it matched up with productivity (around $19 an hour) and they'd pass card check legislation to make it easier for workers to form unions and thus collectively bargain for higher wages.

But that's not what they're doing.

They're trying to cut immigration.

And they're trying to cut immigration because immigrants to the United States these days are way less white than they used to be.

Until 1960s, we limited immigration on the basis of how many people whose ancestors were from any particular country were already in the United States.

Since most Americans in the first half of the last century were white, this was a slick way to keep people who weren’t white out of the country.

That all changed in 1966, when President Johnson signed the Immigration and Nationality Act of 1965, blowing apart the old quota system and ushering in a new era of immigration from Asia, Africa, and Latin America.

Johnson's move was as revolutionary an act as the Voting Rights Act, which conservatives also hate, and they have never really gotten over it.

For example, Pat Buchanan, the godfather of Trumpism, even went so far as to blame the Immigration Act of 1965 for the 2007 Virginia Tech Massacre because the gunman was Korean.

As Buchanan wrote, "Cho was among the 864,000 Koreans here as a result of the Immigration Act of 1965...which threw the nation's doors open to the greatest invasion in history. What happened in Blacksburg cannot be divorced from what's been happening to America since the immigration act brought tens of millions of strangers to these shores."

That would be "strangers of color," if you've never read Buchanan.

As ugly as that sentiment is, it's swarming right below the surface of the entire Republican Party's anti-immigration rhetoric.

The simple reality, as Buchanan would point out, is that they want to "Make America White Again."

They just don't have the guts to say it.