After having pledged to take executive action on undocumented immigrants, President Barack Obama has been signaling that he may postpone any such move until after the midterm elections. The proximate cause appears to be electoral anxiety among a handful of Democrats running for Senate across the South.

Obama's approval rating nationwide has been stuck in the low 40s — dangerous territory. In parts of the South, it's in the 30s, creating a significant drag on Democratic candidacies in Arkansas, Georgia, Kentucky, Louisiana and North Carolina, where Democrats often start their campaign races wearing a partisan leg iron.


Despite huge structural disadvantages — in addition to a Dixiefied map it's a midterm election in the president's second term — Democratic Senate candidates in difficult states have managed to stay within striking distance of their Republican opponents. Most election models, as my Bloomberg View colleague Jonathan Bernstein wrote, give Republicans only a modest advantage in the competition to control the Senate.

Which brings us back to the White House decision. If Obama deferred deportations for millions of undocumented immigrants, both immigration and Obama would become much bigger issues in Senate campaigns. And from North Carolina to Alaska, most Senate Democrats don't want to discuss either Obama or immigration, especially as polls show public opinion turning sour on the importance of legalization and citizenship.

Candidates, their staffs and consultants are all in the business of optimism. Give us money, and we can win. Volunteer, and we can win. Vote, and we can win. And they're not wrong to be optimistic. Individual Democratic candidates across the South — along with those in tight contests in Alaska, Colorado and Iowa — might each pull out a victory. (I don't know where to begin with this Kansas race.) Consequently, they don't want the president tossing up the chess board in hopes that the pieces land more favorably — not when they're just one debate triumph, or one opponent's gaffe, away from eking out a victory.

For each individual Democratic Senate candidate, Obama's restraint makes sense. But for Democrats in general it may not. Under the circumstances, it's hard to believe that enough Democrats will win enough close races to hold on to the Senate. There is very little dynamism in the polls. Consumer confidence has risen recently, but Obama's approval rating hasn't. The Southern tier of Senate races, in particular, has been muddled at best for Democrats since mid-summer. Remember 2012, when Obama maintained a small lead over Mitt Romney week after week after week? The battle for Senate control looks similar, only this time it's Republicans with a small, consistent lead. In addition — Democrats' robust turnout operations aside — Republicans have the more motivated base.

That's where a presidential decision to defer deportations could come into play. It's unquestionably a risk. But so is allowing the continued drift toward a narrow Democratic defeat in November. Executive action might inspire more Hispanics to go to the polls in Colorado, where Sen. Mark Udall is running barely ahead of Republican Cory Gardner. It could also boost turnout among the much smaller Hispanic populations of Georgia, Louisiana and North Carolina. "When you do real things to help real people, real people get real enthused," said a frustrated Frank Sharry, one of Washington's leading immigration advocates.

And it could boost turnout among the sizable black electorate across the South. If Republicans responded to an Obama executive action on immigration with typical levels of personal vitriol and loud noises about impeachment, black voters might well become more engaged. They had the president's back in 2012. If Obama came under sustained attack, they might rise to his defense again.

Either strategy is a crap shoot that leaves many Democratic Senate candidates simultaneously trying to distance themselves from Obama while also trying to motivate black voters. But executive action on deportations would also represent a huge down payment on future Hispanic (and, perhaps to a lesser degree, Asian) votes. The more fiercely contested the move, the more Hispanic voters would understand the political risk Obama was taking on behalf of undocumented immigrants. It could pay electoral dividends to Democrats for years. (It's not certain a post-election move, on the heels of vocal disappointment from immigration supporters, would be as powerful.)

In difficult election environments, consultants generally prefer races to be atomized and less subject to national tides. That's no doubt true for Democratic consultants this year. But there is a price to disappointing supporters. And if the dynamics of this election aren't scrambled, Obama's deference to Southern Democrats may still not be a route to victory. Deference on immigration might keep key candidates from losing big. Can it make them win?

Francis Wilkinson writes editorials on politics and domestic policy for Bloomberg View.