Paying a company's tax bill doesn't increase the taxes of shareholders in a company, and there's no other problem with my stance. Buffett is CEO of Berkshire Hathaway, and with Charlie Munger, his vice-chair, they have a voting majority, so they can dictate settlement in full with the IRS. Buffett's financial position in Berkshire Hathaway is sufficient that he could quit less than 1% of his shares and mandate the proceeds be used to settle all potential back taxes. Berkshire Hathaway is not like your normal, publicly-traded, 300 billion dollar company. It's essentially a cotton mill turned one-man-mutual fund built on opportunistic investing, a vampire entity feeding on failure, from upside-down insurance companies in the 60's to the recent bailouts of speculative banks. One Class A share of Berkshire Hathaway costs over $100,000, and peaked above $150,000. It's a big Rube Goldberg-esque contraption of industries, securities, and financial instruments that the richest in the world treat like a giant sandbox filled with incorporated toys and money. My argument is that the billionaires' toy, in a world where the global economy has been minutes from meltdown twice and digital runs on banks have occurred faster than a human could react to them, the corporate essence of the billionaires has a moral and ethical responsibility to good global citizenship in their home country long before the American individual should pony up a penny more. And Berkshire Hathaway is only the worst offender, companies like GE also fight tooth and nail to keep money from the IRS, from just not paying hundreds of millions of dollars to lobbying for tax loopholes that benefit corporations. The billionaires that aren't paying their fair share are the corporations, not the people.
OK you've convinced me on Buffett and I concede the point. If his company is speculating in the way you describe, his business is part of the problem and should be taxed out of existence.