Combine them and the $600 billion on income security, and you get about $2 trillion, which is enough to fund a huge chunk of it.
I don't understand the how McArdle thinks that $12,000 per year is too austere for most people to live comfortably on and simultaneously decries how it will make many people drop out of the workforce. She should address what (many) advocates of it want.
Political concerns are, of course, another question.