This is where four years of planning come in handy. Mr. Romney built a campaign war chest and a pro-Romney super PAC. The Romney campaign and the outside organization could spend millions on ads and mailers taking down rivals, allowing the candidate to remain above the fray and concentrate on his more positive message.

That message, by contrast to 2008, has been focused, unwavering, relentless. Mr. Romney has taken positions and stuck with them, even if it has meant defending the likes of RomneyCare. In Iowa, New Hampshire and everywhere else, voters have heard—again, and again, and again—the same two messages: He has the business and management experience to competently turn around the country, and he is the most electable against Mr. Obama…

So while Mr. Romney may not excite them, while he may not be ideal, in light of the other candidate’s problems, and given the election stakes, voters are buying his argument that he is, well . . . good enough. Which is why, barring a surprise, or a late entrant, Mr. Good Enough—through good fortune, dogged determination, and the skillful elimination of his rivals—may end up grabbing the conservative ring in this all-important election year.