In just 16 days, a presidential campaign that has raged for almost two years will at last come to an end.

In that time, America has undergone profound changes. And for most Americans, those changes have not been for the better.

When the first, absurdly early straw polls were taken in Iowa in 2007, America was torn by a war in Iraq that seemed unwinnable. But the economy seemed reasonably sound.

That preoccupation with the war may help explain why Republicans passed over Mitt Romney’s successful record of job creation in favor of war hero and foreign-policy specialist John McCain. On the Democratic side, Illinois Sen. Barack Obama, who wasn’t even in Congress when the war began, bested Sen. Hillary Clinton in part because she voted to authorize the war.

Americans, as we now know, wanted change.

But as this race nears the finish line, America’s priorities have changed, too.

The “surge” has reduced the level of violence in Iraq and President Bush has begun modest troop withdrawals. Sens. McCain and Obama differ mostly about the details and pace of future withdrawals.

But the speed and virulence of the worldwide liquidity crisis, caused by the collapse of the junk mortgage market, has stunned most Americans and has led voters, who now review their shrinking retirement funds and rising unemployment rates with alarm, to focus overwhelmingly on America’s economic ills.

Given this inescapable economic agenda, The Post believes Barack Obama is better equipped to lead America back to a prosperous future.

It’s time to change course.

Frankly, neither Obama nor McCain has a comprehensive plan to end the economic crisis, or to even calm our jittery nerves. But Obama’s promise to surround himself with this country’s top economic thinkers, such as Warren Buffet, is at least somewhat comforting.

In unsteady times, it may seem obvious to gravitate toward the veteran politician, but in this campaign, it’s been the newcomer who has had the steady hand.

This fast-breaking global meltdown overwhelmed both campaigns and the final weeks of a hard-fought political contest are hardly the place for the cool, bipartisan thinking needed to get us out of this mess. Fortunately, bipartisan efforts by the Bush administration and Congress have at least bought America time to begin crafting long-term economic reforms.

Looking at McCain’s and Obama’s specific proposals, we unfortunately find much to dislike in both port- folios. We can live with Obama’s call to raise taxes on families earning more than $250,000 a year. And, in fact, we’ve long thought it fiscally irresponsible to wage two wars on tax cuts.

However, we’re concerned he may increase capital gains taxes at a time when the economy is starved for investment capital. Indeed, we’d favor eliminating capital gains taxes entirely if such profits are reinvested in another enterprise within one year.

We also would urge Obama to expand investment tax credits for businesses, to put profits back to work creating new jobs.

America’s other most pressing long-term economic problem is health care.

Obama’s plan, while not perfect, is far superior to McCain’s catastrophic ideas. How does it affect the economy?

Consider this: General Motors now pays more than $1,500 for health care benefits, mostly for retired employees, on each new car sold.

America’s competitors in Japan, Germany and China don’t share such costs because their national health care plans are funded through broad-based taxes. Somehow, America must level the playing field.

McCain wants to eliminate the corporate tax deduction on existing health care plans, a cruel corporate surtax averaging $3,500 per employee. That tax hike would force employers to drop coverage for tens of millions of workers. The lucky workers who still had employer-paid benefits would have to pay income taxes on them — a $3,000 tax increase on a typical middle-income Colorado worker. And this massive tax increase on employers and employees alike comes from a man who asked repeatedly in the last debate: “Why raise anybody’s taxes?”

Why, indeed, Sen. McCain?

We can’t imagine a Democrat- controlled Congress would pass McCain’s reckless health care tax. But even proposing such a scheme shows his woeful lack of understanding of America’s economic underpinnings.

As to Obama, we confess we fear that a compliant Congress may be all too eager to approve his plans. That’s why it’s critical for him to reach across the aisle and draw the best team he can assemble to get America working again. Why not ask Romney to chair his health-care reform task force, or even serve as his economic recovery “czar”? There’s precedent for such a move, since Wendell Willkie helped sell President Franklin D. Roosevelt’s vital wartime lend-lease program after losing his presidential race to FDR in 1940.

What’s the chance that Obama will reach out in such a bipartisan fashion? Actually, he has a long record of doing exactly that. We don’t mean his brief tenure in the Senate so much as his successful run as a community organizer in Chicago.

Republicans love to mock Obama’s history as a community organizer. But here was a man with no money to offer, no patronage to dispense, no way to punish his opponents. All he could do was to work with people from all walks of life, liberals and conservatives, business people and the unemployed, and bring them together in common cause for a better community. Could there really be better preparation to reunite a worried and divided America to again pursue our “more perfect union”?

If Americans were only worried about foreign affairs, McCain’s stalwart service in the military and experience on the national stage would make him the more credible commander in chief. But our eyes have turned homeward and, in this hour, Obama has the eloquence and vision to bring us back together.

As novelist Christopher Buckley said in endorsing Obama, the Illinois senator “has a first-rate intellect and a first-rate temperament.”

With the help and prayers of the American people, we believe those talents can also make Barack Obama a great president.