What the Democrats mean is the border is secure enough to keep out any people who might in the future vote Republican. Passports are still examined at international airports and undocumented rich people are turned away. Educated, employable people from northern European nations will not pass. That said, the squalid masses of unemployable impoverished people from proto-Marxist countries who believe socialism is the answer and feel Obama is a god king of unlimited handouts, those people can cross the secure border in the tens of millions.