Oftentimes, it’s difficult to pick a winner in a presidential debate, but this time there was no question that Mitt Romney dominated. Throughout the night, Romney was the aggressor – dissecting President Obama’s record and policies on the economy, health care, deficits and energy while explaining his different approach. He was articulate, passionate and totally relaxed and even funny at times.

It was a far cry from Romney’s detached, robotic image. The best part of his debate performance was how specific he got. For instance, when criticizing Obama’s financial regulatory reform, he didn’t merely give a generic Republican attack on “regulation” – he explained the unintended consequences of creating too big to fail banks and how it hurts smaller community banks. When it came to tax policy, he described how Obama’s plan to raise taxes on “the rich” would actually hurt a typical small business and make them less likely to hire. We’ve heard Romney tell us again and again that his private sector experience means that he knows how the economy works, but tonight he showed us. When Obama attacked tax subsidies to oil companies, Romney pointed out that Obama gave 50 years worth of such tax breaks to green energy companies, many of which failed. The $90 billion in subsidies, he noted, would be enough to hire two million teachers.

In contrast to Romney, Obama came out extremely weak. He fell into talking points and long, drawn out answers that didn’t seem to accomplish anything. He struggled to find words at times and wasn’t always coherent. He was rattled, even asking moderator Jim Leher one time if he wanted to move on from the tax discussion. At times, he was staring off screen, almost checked out from the action. Surprisingly, he didn’t even do an effective job explaining to voters the similarities between Romneycare and Obamacare. His strongest moment came when he pointed out that Romney has left out a lot of key details from his proposals, but Romney even had an answer for that, that he wanted to work with members of Congress and didn’t want to dictate plans to them.

If debates still have the ability to move votes, Romney will get a bounce out of tonight. In market terms, Obama’s lead in the polls “priced in” the expectation that he would dominate the debates, so this strong performance by Romney will likely tighten the race.

All of this said, there are two reasons conservatives should keep their exuberance in check. In past elections, it isn’t uncommon for the rusty incumbent to come off lousy in the opening debate. This was the case when Walter Mondale won the first 1984 debate against Ronald Reagan and John Kerry won the first debate against George W. Bush. In both cases, the incumbents recovered in the subsequent debates, and ended up winning the election.

Another reason for caution is that Romney, as part of his efforts to disarm Obama’s criticisms, made a number of policy concessions that could box him in and make it more difficult for him to govern as a limited government conservative if elected. At various times during the debate Romney said that he wasn’t interested in cutting taxes, particularly on the wealthy; that he would cover individuals with pre-existing conditions; that he wouldn’t touch Medicare and Social Security over the next decade and would be willing to give more money to seniors for prescription drugs; and that he’d be open to hiring more teachers. Should he be elected president, all of the major fights – repealing Obamacare, overhauling the tax code and reforming entitlements – will trigger a massive campaign by liberals to portray him as trying to hurt the poor to the benefit of the rich. If he is so willing to concede policy points during the campaign, will he fight for limited government as president?