Yesterday, a number of free-market economists and advocates voiced concern about the central feature of Rick Santorum’s economic policy. In short, Santorum picking winners (manufacturing) and losers (non-manufacturing) is no better than President Obama doing it — neither has the expertise to outwit the free market. Moreover, given that manufacturing has improved productivity (by slimming down while raising output), a zero tax rate for such firms isn’t likely to be the best way to promote jobs. These are firms that have succeeded by minimizing their workforce.

Other conservatives are beginning to fret about Santorum’s economic record as well. Phil Klein, who has been about the most ferocious critic of Mitt Romney out there, says of Santorum: “As a Senator from Pennsylvania, Santorum took earmarks, pushed a support program for dairy farmers, sided with unions and backed steel tariffs. In these instances, when free market principles clashed with local concerns, he abandoned limited government conservatives.” Phil’s colleague Conn Carroll goes even further, arguing, “Santorum is a perfectly decent alternative Romney. He may even be a more electable alternative to Romney. But he is not a conservative alternative to Romney.” Well, not economically more conservative, perhaps.

Let’s be honest: Neither of these guys is as fiscally conservative (or as consistent) as Rep. Paul Ryan (R-Wis.), to pick an example.

Club for Growth described Santorum’s record this way: “On the whole, Rick Santorum’s record on economic issues in the U.S. Senate was above average. More precisely, it was quite strong in some areas and quite weak in others. He has a strong record on taxes, and his leadership on welfare reform and Social Security was exemplary. But his record also contains several very weak spots, including his active support of wasteful spending earmarks, his penchant for trade protectionism, and his willingness to support large government expansions like the Medicare prescription drug bill and the 2005 Highway Bill. As president, Santorum would most likely lead the country in a pro-growth direction, but his record contains more than a few weak spots that make us question if he would resist political expediency when it comes to economic issues.” In particular, would he stand up to the spending addiction of both Democrats and Republicans? Not clear.

Romney doesn’t have a record of protectionism or Big Labor coziness. But if Santorum has No Child Left Behind (the quintessential top-down federal government program) and Medicare Part D ( an unpaid for entitlement, albeit with market features), Romney has RomneyCare. However, on spending, Romney’s record may actually be superior to Santorum’s. CFG put it this way: “The Massachusetts Legislature was (and continues to be) dominated by Democrats more interested in raising taxes than cutting government programs. Throughout his tenure, Romney’s proposed cuts were met with opposition while the vast majority of his vetoes were relegated to the graveyard of overrides. On balance, his record comes out more positive than negative, especially when one considers that average spending increased only 2.22% over his four years, well below the population plus inflation benchmark of nearly 3%.” He also “attempted to cut down on government spending by streamlining many duplicative and wasteful elements of Beacon Hill. Some of his more ambitious proposals were rejected by his uber-liberal Legislature.”

In short, neither one of these candidates is a government minimalist. Romney, as a man marinated in the private sector, may be more conservative than Santorum on tax, spending, trade and labor issues. On tax policy, Santorum’s manufacturing-friendly proposal is bad tax policy; Romney’s plan is yet to be unveiled. On health policy, Romney’s past continues to haunt him.

So more than specific issues, the real choice is between two different sorts of candidates. Santorum — hard-charging, pugnacious, confrontational and inclined to use economic policy for social ends — couldn’t be more different than Romney — methodical, experienced in give-and-take with a Democratic legislature, a cheapskate on spending and less aggressive but more market-oriented in his tax policy. One is a combatant, the other a CEO. One is experienced in leading government and creating an agenda; the other is not. If Santorum could run the campaign and Romney run the presidency, the Republicans might be on to something.

But primaries, like all elections, require a choice between imperfect candidates. Voters will need to consider which, if elected, is best equipped to help jump-start the economy, relieve the burdens on the private sector imposed by Obama and push forward on a real fiscal reform program.