In his speech to CPAC today, Donald Trump attacked advocates of immigration reform, including on-and-off supporter Marco Rubio, arguing that undocumented immigrants shouldn’t be given a pathway to citizenship because he thinks they won’t vote Republican.

The faux-presidential candidate said that immigration will actually destroy America: “Immigration, we’re either a country or we’re not, we either have borders or we don’t; you have a border, you have a country and if you don’t have a border, what are we just a nothing? A nothing.”

Trump added that he understands why many people at CPAC are “so conservative you don’t even want to be a Republican.”

“If you let the 11 million — which will grow to 30 million — people in, I don’t care who stands up, whether it’s Marco Rubio and talks about ‘let everybody in,’ you won’t get one vote, every one of those votes goes to the Democrats,” Trump said. “Of those 11 million potential voters, which will go to 30 million in the not too long future, you will not get any of those votes no matter what you do, no matter how nice you are, no matter how soft you are, no matter how many times you say ‘rip down the fence and let everybody in,’ you’re not going to get the votes.”

“So with immigration, you better be smart and you better be tough and they’re taking your jobs and you better be careful.”