WASHINGTON (MarketWatch) — Of all the falsehoods told about President Barack Obama, the biggest whopper is the one about his reckless spending spree.

As would-be president Mitt Romney tells it: “I will lead us out of this debt and spending inferno.”

Almost everyone believes that Obama has presided over a massive increase in federal spending, an “inferno” of spending that threatens our jobs, our businesses and our children’s future. Even Democrats seem to think it’s true.

Government spending under Obama, including his signature stimulus bill, is rising at a 1.4% annualized pace — slower than at any time in nearly 60 years.

But it didn’t happen. Although there was a big stimulus bill under Obama, federal spending is rising at the slowest pace since Dwight Eisenhower brought the Korean War to an end in the 1950s.

Even hapless Herbert Hoover managed to increase spending more than Obama has.

Here are the facts, according to the official government statistics:

• In the 2009 fiscal year — the last of George W. Bush’s presidency — federal spending rose by 17.9% from $2.98 trillion to $3.52 trillion. Check the official numbers at the Office of Management and Budget.

• In fiscal 2010 — the first budget under Obama — spending fell 1.8% to $3.46 trillion.

• In fiscal 2011, spending rose 4.3% to $3.60 trillion.

• In fiscal 2012, spending is set to rise 0.7% to $3.63 trillion, according to the Congressional Budget Office’s estimate of the budget that was agreed to last August.

• Finally in fiscal 2013 — the final budget of Obama’s term — spending is scheduled to fall 1.3% to $3.58 trillion. Read the CBO’s latest budget outlook.

The big surge in federal spending happened in fiscal 2009, before Obama took office. Since then, spending growth has been relatively flat.

Over Obama’s four budget years, federal spending is on track to rise from $3.52 trillion to $3.58 trillion, an annualized increase of just 0.4%.

There has been no huge increase in spending under the current president, despite what you hear.

Why do people think Obama has spent like a drunken sailor? It’s in part because of a fundamental misunderstanding of the federal budget.

What people forget (or never knew) is that the first year of every presidential term starts with a budget approved by the previous administration and Congress. The president only begins to shape the budget in his second year. It takes time to develop a budget and steer it through Congress — especially in these days of congressional gridlock.

The 2009 fiscal year, which Republicans count as part of Obama’s legacy, began four months before Obama moved into the White House. The major spending decisions in the 2009 fiscal year were made by George W. Bush and the previous Congress.

Like a relief pitcher who comes into the game with the bases loaded, Obama came in with a budget in place that called for spending to increase by hundreds of billions of dollars in response to the worst economic and financial calamity in generations.

By no means did Obama try to reverse that spending. Indeed, his budget proposals called for even more spending in subsequent years. But the Congress (mostly Republicans but many Democrats, too) stopped him. If Obama had been a king who could impose his will, perhaps what the Republicans are saying about an Obama spending binge would be accurate.

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Yet the actual record doesn’t show a reckless increase in spending. Far from it.

Before Obama had even lifted a finger, the CBO was already projecting that the federal deficit would rise to $1.2 trillion in fiscal 2009. The government actually spent less money in 2009 than it was projected to, but the deficit expanded to $1.4 trillion because revenue from taxes fell much further than expected, due to the weak economy and the emergency tax cuts that were part of the stimulus bill.

The projected deficit for the 2010-13 period has grown from an expected $1.7 trillion in January 2009 to $4.4 trillion today. Lower-than-forecast revenue accounts for 73% of the $2.7 trillion increase in the expected deficit. That’s assuming that the Bush and Obama tax cuts are repealed completely.

When Obama took the oath of office, the $789 billion bank bailout had already been approved. Federal spending on unemployment benefits, food stamps and Medicare was already surging to meet the dire unemployment crisis that was well underway. See the CBO’s January 2009 budget outlook.

Obama is not responsible for that increase, though he is responsible (along with the Congress) for about $140 billion in extra spending in the 2009 fiscal year from the stimulus bill, from the expansion of the children’s health-care program and from other appropriations bills passed in the spring of 2009.

If we attribute that $140 billion in stimulus to Obama and not to Bush, we find that spending under Obama grew by about $200 billion over four years, amounting to a 1.4% annualized increase.

After adjusting for inflation, spending under Obama is falling at a 1.4% annual pace — the first decline in real spending since the early 1970s, when Richard Nixon was retreating from the quagmire in Vietnam.

In per capita terms, real spending will drop by nearly 5% from $11,450 per person in 2009 to $10,900 in 2013 (measured in 2009 dollars).

By the way, real government spending rose 12.3% a year in Hoover’s four years. Now there was a guy who knew how to attack a depression by spending government money!