The following is a political ad, so obviously it's not objective. But as far as I can tell it's factually accurate. Romney really did make those false accusations, and they are indeed false. This isn't to say that Obama doesn't stretch the truth -- he does -- but he hasn't made quite the same career of telling repeated blatant lies about political opponents.
Steve Benen has been publishing a weekly list of false statements by Romney -- most of them dishonest attacks on fellow Republicans and on Obama. Here's just a very small sampling of recent examples (my phrasing, not Benen's):
- Romney claimed that Obama's "vision is that it is ok for a small business to raise taxes from 35% to 40% of small businesses." Obama has successfully pushed for reducing taxes on small businesses. Romney appears to be talking about Obama's proposal to allow a return to income tax rate during the 1990s economic boom. The top rate of 39% would apply to only to the portion of annual taxable income over about $350,000 and would still be far below the top rate in effect during most of Reagan's presidency. Note that for the tiny fraction of small business owners who take home that much, the tax applies only to their personal income, not the gross receipts of the business. (Full disclosure: I co-own a small business.)
- Romney claimed Obama "is taking America on a path towards Europe and Europe is not working there. It will not work here." In fact, what's not working in Europe is the foolish "austerity" Romney thinks will solve our problems.
- Romney claimed that "Syria is Iran's source of access to the Mediterranean." Look at a map. Syria shares no border with Iran; Iraq is in the way. (Perhaps Romney having dumped the gay foreign policy adviser Romney has taken on a recent Miss Teen South Carolina as foreign policy adviser?)
- Romney said that in Obama's "campaign kickoff speech last week, he asked us not to think about these last four years... The president's plea that we simply ignore the last four years is his latest effort to escape responsibility for the failures." In reality, Obama urged voters to remember the last four years.
- Romney said, "Old-school liberals saw a problem and thought a government-run program was the answer. Obamacare is the fulfillment of their dreams." But the Affordable Care Act is designed around private insurance, just like the system Romney introduced in Massachusetts that "Obamacare" very nearly duplicates.