What's impossible to know, however, is whether things would have been far worse for the economy and markets without the Bush tax cuts.
For many Americans, the best argument -- maybe the only argument -- for higher tax rates in 2010 would be the need to deflate the ballooning federal budget deficit. That was a crucial element of the case for the Clinton tax increases of 1993.
Whether by policy or just good luck, the deficit did indeed shrink in the 1990s and briefly turned into a surplus by the end of the decade.
But the great risk in trying to use tax increases to drive down the deficit today is that many Americans, even the well-off, are in weak financial positions because of their debt loads, dwindled investment accounts and lack of wage growth. Cut income further, and consumption could dive.
U.S. Chamber of Commerce President Tom Donohue stirred that pot with gusto this week, warning in a speech that the Obama administration's plan for tax increases and new regulations on businesses is "a surefire recipe for a double-dip recession, or worse."
For investors who believe that 2010 will bring enough tax hikes to sink the economy, there shouldn't be much debate about what that would mean for stock prices. A turn back to recession -- and tumbling corporate earnings -- wouldn't support a Dow Jones industrial average of 10,600.
Even if the economic recovery and the stock market's revival survive any tax increases this year, some Wall Street pros say that rising tax rates should be viewed in combination with other potential threats to the market's long-term health.
Jason Trennert, chief investment strategist at Strategas Research Partners in New York, figures there are four principal variables that affect the prices investors are willing to pay for stocks relative to companies' underlying earnings: taxes, regulation, interest rates and inflation.
For much of the last 30 years, he notes, all four of those variables were declining, helping to fuel what was a spectacular run for stocks in the 1980s, 1990s and even 2000s (for many issues) before the crash of 2008.
The challenge to the case for a powerful long-term bull market, Trennert says, is that all four of those variables seem to have only one way to go from here: up.
