Coining a phrase that seems destined to become his new campaign slogan, Mitt Romney needed only three words tonight to accept the Republican Presidential nomination: I bought it. Those words had a special meaning for Mr. Romney, who had to spend seventy million dollars in the G.O.P. primaries to defeat a serial adulterer, a former pizza executive, and a crackpot in a sweater-vest. It has been an up-and-down convention for Mr. Romney, who was largely ignored at Tea Party rallies early in the week but later picked up a key endorsement from his wife. Tonight, however, was a time to reflect, as he put it, on money well spent. Our opponents say that America is in decline, that it is no longer number one, he said. I say our democracy is the best that money can buy. Mr. Romney braided his speech with the theme of I bought it, reminding his audience that in order to take the White House, I have millions to go before I sleep. He made an emotional appeal to a group he called the single-issue billionaires, imploring them, Let me know what you want. Eliminate the E.P.A.? Bomb Iran? Mitt Romney is open for business. The audience roared its approval. Mr. Romney made one reference to his running mate, Rep. Paul Ryan (R., Wisc.): Dont let his crazy rock-and-roll playlist fool you. Hes serious about the important things: cutting taxes for the rich and ending Planned Parenthood. Ultimately, he ended his speech with a rousing call to arms that brought the Republican audience to its feet: The road to the White House will be hard, and strewn with challenges. But together, theres nothing we cant buy. 