It might seem surprising that the Mitt Romney camp is essentially ignoring Herman Cain and continuing to lambaste Texas Gov. Rick Perry. But, as the National Journal points out, the Romney team appears to have taken the view that only Perry could mount a real challenge. This, by the way, is not unlike the John McCain 2008 presidential campaign that went after Romney when he was still in single digits; the McCain people understood that Romney had the money and organization to challenge him.

The Romney team’s assessment seemed vindicated last week when Cain began to self-destruct. Indeed, not only does Romney want to avoid piling on the amiable Cain, but he recognizes that Cain is playing a useful role in subdividing the votes of hard-core conservatives.

The “enemy of my enemy” is an apt description of Romney’s current strategy. Rep. Michele Bachmann (R-Minn.) may no longer be a threat in his mind to grab the nomination, but the Romney team couldn’t be more delighted that she continues to throw darts at Perry.

The risk for Romney is that they give undue attention to Perry, who is languishing in single digits in Iowa and New Hampshire polls. Perry may get his second wind battling against the moderate Romney.

But the Romney team is arguably overlooking one significant threat: Perry is about to launch a tax and entitlement reform package. When I ask Romney advisers if their candidate will do the same, I hear two things: 1) We already did that in the 59-point plan and 2) we will get more specific as time goes by. But the 59-point plan has limited proposals: keeping the Bush tax cuts, eliminating the death tax, lowering the corporate tax and coming up with a middle-class tax break on capital gains. What is missing is the sort of comprehensive plan that Rep. Paul Ryan (R-Wis.) has put forth.

As for entitlement reform, Romney has taken a meat cleaver to Perry for suggesting Social Security be devolved back to the states. But as for his own ideas, his 59-point plan says only this: “With respect to Social Security, there are a number of options that can be pursued to keep the system solvent — from raising the eligibility age to changing the way benefits are indexed to inflation or high-income retirees. One option that should not be on the table is raising the payroll tax or expanding the base of income to which the tax is applied.”

A white paper gets a tad more specific but only repeats these two options, without choosing one:

His starting point in addressing Social Security is the basic principle of keeping our promises both to current seniors and to future generations. Romney agrees with the program’s many critics who express deep concern about the long-term financial health of the program. But he parts company with anyone who believes those financial problems require dismantling the program itself. Instead, he has elaborated a number of options that can keep the program solvent without having either to raise the payroll tax or to expand the base of income to which the tax is applied.One such approach is gradually increasing the retirement age. . . . An alternative or perhaps complementary approach would be to change the way the initial Social Security benefit is calculated for high-income individuals. Currently, the initial benefit for all recipients is keyed to their average lifetime earnings and inflated to current-year values to reflect changes in the overall economy. But the factor used in calculating that inflation is not the consumer price index (CPI), but rather the wage index. Because wages have gone up much faster than consumer prices over the years, the wage index raises the starting point for Social Security benefits more rapidly than would be the case if the CPI is used.

Romney does not, however, tip his hand as to which of these options he will employ.

On Medicare Romney’s jobs plan says that “with respect to Medicare, the plan put forward by Congressman Paul Ryan makes important strides in the right direction by keeping the system solvent and introducing market-based dynamics. As president, Romney’s own plan will differ, but it will share those objectives.” Why not tell us what it is?

On Medicaid he does better: “As president, Romney will push for the conversion of Medicaid to a block grant administered by the states. This approach could save the federal government over $200 billion each year by the end of the decade, while also providing states with the flexibility to develop innovative and effective approaches best suited to their needs.”

The danger for Romney is that Perry comes up with substantive Social Security, Medicare and tax reforms, leaving Romney looking like he’s the one lacking concrete ideas. Maybe Perry’s plan will turn out to be fluff and even less specific than Romney’s, but it’s not clear why the Romney team (as it did in the jobs plan with regard to energy, regulations, labor and spending reduction) is shying away from offering more particulars in these areas. It’s not like he’d have to start from scratch. The Ryan Medicare and Social Security plans are out there. The Simpson-Bowles commission addressed entitlement reform in a serious way. And Sens. Joe Lieberman (I-Conn.) and Tom Coburn (R-Okla.) also offered meaty ideas.

Moreover, Romney should know that the surest way to keep Perry and others at bay is to offer his own bold reforms. His jobs plan and white paper suggest that he’s thought a lot about these issues. What is missing is a decisive presentation for the Romney solutions to Social Security and Medicare. He’s had successful policy rollouts on jobs and foreign policy. Why stop now?