Unless you’ve been smart enough to avoid the news entirely for the last few weeks, you know that tomorrow marks President Obama’s first 100 days in office. But you may not know that the “100 days” phrase didn’t start with FDR, but with Napoleon.

William Safire’s Political Dictionary tells us that it originally marked the period between the little dictator’s escape from Elba and rampage across Europe before his final defeat at Waterloo.

So perhaps the question to ask about presidents’ first 100 days is, how much damage has our new Emperor done? In Obama’s case, the answer is, a lot. He’s made a running start toward transforming the federal government’s role in the economy and — if such a thing is even possible — further expanding the president’s role in American life.

On the bright side, though, at least this president has a sense of humor. How else can we interpret his offer to cut $100 million from a $3.9 trillion federal budget? Economist Greg Mankiw puts those numbers in perspective:

“Imagine that the head of a household with annual spending of $100,000 called everyone in the family together to deal with a $34,000 budget shortfall.” The new austerity plan? One fewer latte at Starbucks this year — the rest goes on the credit card.

Thus far, Obama has signed into law a major expansion of children’s health insurance and a $787 billion “stimulus” package that ramps up federal involvement in health care and education — spending that’s unlikely to shrink when the economy rights itself.

The projected $1.8 trillion deficit for the current fiscal year equals the entire federal budget in 2000. But have no fear, taxpayers: Obama’s going to ease your burden by forcing the Department of Homeland Security to buy its supplies in bulk and cancel some magazine subscriptions.

This is a president with grand plans and vast powers. He promises a “cure for cancer in our time” and views his budget as a “blueprint” for the entire American economy. This is a president who can fire the CEO of GM without so much as a courtesy call to major shareholders — a president who wants new powers allowing him to preemptively seize financial institutions deemed “too big to fail.”

But this president sweats the small stuff as well. Not a sparrow falls without our National Father noticing — and offering a seven-point plan for sparrow recovery. Last week, Obama assured Americans that the days of hidden credit card fees are over.

That followed upon his April 9 infomercial-style TV appearance urging you to take advantage of low interest rates and refinance your mortgage! This is a president who stands behind the warranty on your Chevy Suburban. You’re not gonna pay a lot for this muffler! POTUS commands it.

A raccoon-eyed Dick Cheney, newly emerged from his underground bunker, growls that Obama is shrinking presidential power in national security. It’s hard to see how that’s so. Hype and Hope aside, Obama’s anti-terror policies don’t differ that much from the Bush-Cheney approach.

Obama’s Justice Department has fought to retain most of the Bush-era powers governing enemy combatants and surveillance. They’ve embraced the Bush-Cheney position that the State Secrets Privilege bars the courthouse door to litigants who claim they’ve been harmed by warrantless wiretapping.

Worse, according to constitutional lawyer Glenn Greenwald, the Obama DOJ has gone even further than the Bush team, arguing that “all claims of illegal government surveillance are immunized in the absence of ‘willful disclosure’ to the public of the intercepted communications.”

Conservatives who recently screamed bloody murder over a DHS report targeting “right-wing extremists” (including pro-lifers and gun enthusiasts) ought to ask themselves if it was such a good idea to have fought relentlessly to expand federal wiretapping powers over the last eight years.

So far, Americans seem broadly tolerant of Obama’s power grab. In a recent Gallup poll, 86 percent think he’s met or exceeded early expectations. But danger lurks for Obama in some of Gallup’s numbers. More Americans reject an expanded role for government in fighting the financial crisis than support it, and only 13 percent want the expansion to be permanent.

Despite current appearances, Americans retain a healthy streak of anti-statism. Obama’s overreaching may eventually lead to his Waterloo.