The undecided New Hampshire voter has just two weeks to answer this question: Why switch from Barack Obama to Mitt Romney? By now the question is easy to answer if one has been listening to the candidates.

Barack Obama was in Manchester on Thursday. When he came to Veterans Park in 2008, he sold “hope and change.” He was uplifting, inspiring. Last week, that was gone. In its place was the negativity, the deception, the nastiness that Obama once said he wanted to remove from politics.

Obama offered New Hampshire nothing but bitterness and envy. He attacked Romney with a litany of mischaracterizations and deliberate falsehoods.

It was far from the uplifting message Obama delivered four years ago. But four years ago Obama did not have an indefensible record.

He could say that investing billions in high-speed rail and solar energy and electric cars and college loans and road repair was the path to prosperity, and many found it plausible. Now, when he offers the exact same proposals, as he did on Thursday, we can look back at the last four years and note that he has done all of those things and they did not work.

What Obama offers America is a fantasy. Sputtering economies are not sparked back to life by government-directed spending on industries hand-chosen by politicians. They are revived by unleashing the energy and creativity of the American people.

The key difference between Mitt Romney and Barack Obama is that Romney understands that crucial economic truth; Barack Obama does not.

That is why Romney offers not “tax cuts for the rich,” but true and long overdue tax reform that cuts everyone’s tax rate and closes loopholes that actually make our tax code less fair. It is why Romney offers regulatory reform that would reduce burdens on businesses so they can hire more people. It is why Romney would bring federal spending back to 20 percent of GDP as opposed to the nearly 23 percent Obama prefers — but does not pay for.

While Obama offers rhetoric and pipe dreams, Romney offers a real plan to bring the economy back to life. It is not the George W. Bush plan. Bush spent more than he took in. Obama, who doubled Bush’s level of deficit spending, accuses Romney of wanting to return to Bush-type deficit spending. It is not true, but if it were, that would be an improvement over the last four years.

Obama had four years — half of them with a Democratic majority in Congress — to try his way. Romney offers a better way, a realistic way, to restore American prosperity. We tried the fantasy. It did not work. Now it is time to stop dreaming and start growing again.