President Obama is heading to Florida today to address the same group of Hispanic legislators who heard Mitt Romney take a more conciliatory line on illegal immigrants. Romney’s walk back of his previous opposition to the substance of the DREAM Act is a good idea, and he was right to point out that the president’s election year decision to stop the deportation of young illegals is cynical. But it isn’t likely to gain him much traction with Hispanic voters. On this issue, he needs to quit now while he’s behind.

Though many pundits have been hounding Republicans to do more to appeal to Hispanics, at least as far as 2012 is concerned it’s a lost cause. Romney should not be tempted to waste any more time trying to outbid the president on an issue where he has far more to lose than to gain by changing his position. Any further shifts on immigration — an issue on which he staked out a hard right-wing position during the Republican primaries — will only remind voters of his reputation as a flip-flopper. In doing so, Romney also seems to be forgetting that the reason why he did his best to outflank Rick Perry and Newt Gingrich on immigration is that his opposition to amnesty programs happens to be popular.

President Obama may have spent most of his presidency ignoring the wishes of his Hispanic supporters who wished him to use his executive power to stop enforcement of immigration laws. But now that he has belatedly done as they asked, Romney is in no position to keep up with the president on the issue. That demonstrates the power of incumbency, but even if the president hadn’t changed his position, the idea that there was a massive opening for Romney with Hispanic voters was probably always something of a myth.

It should also be remembered the assumption that the Hispanic vote is monolithic is also mythical. The community is really several groups whose members identify more strongly with their country of origin than the amorphous Hispanic tag. Cuban-Americans do not generally treat the plight of undocumented aliens from Mexico or Central America as a top issue. Nor do Puerto Ricans who are already American citizens.

Also forgotten in the rush to win the loyalty of Hispanics is the fact that in many key states, there are still far more votes to be won by taking a stand against illegal immigration than for it. It is possible that there is a large enough constituency that regards illegal immigrants with sympathy in swing states like Colorado and Nevada to reward the president for his stand. But the no deportation order could represent the end of his hopes in Arizona, where anger about the government’s failure to protect the border is far greater. The same could be true of other states where Romney’s previous tough stance was not a weakness.

There is good reason for both the president and his challenger to endorse the substance of the DREAM Act. But even if he thought it was in his interest to do so, Romney has to understand this is a losing fight and move on. The less attention he pays to the issue the better off he will be.