So what’s the difference between means-testing and just collecting a bit more taxes? The answer is, class warfare — not between the rich and poor, but between the filthy rich and the merely affluent. For a tax rise would get a significant amount of revenue from the very, very rich (because they have so much money), while means-testing would end up imposing the same burden on $400,000 a year working Wall Street stiffs that it imposes on billion-a-year hedge fund managers... What we need is actual control of health costs. Means-testing of Medicare is just a badly designed, unfair form of taxation.
Of course part of the issue is what do we mean by means? Is it income or total wealth. If I have been frugal all my life and have a bit stashed away for my old age yet do not make a massive amount in what is called income, namely I get interest and dividends, then what am I taxed upon? The Baby Boomer who blew everything and has a sky high mortgage and a trophy spouse gets the benefit of my frugality?
That is another way to look at Krugman's stand. Namely not just what you are earning but what you have created. If you have just destroyed whatever wealth you have, albeit your choice, then I have no duty to bail you out.