For all the discussion about the economy in last night’s presidential debate and on the campaign trail, one key topic that the incumbent and his challenger have largely been silent about is what to do about the once-mighty engine of housing in America’s economy – and how it might get stoked once again.

As our AOL colleague Teke Wiggin, at AOL Real Estate, notes:

That may be because, for President Barack Obama and GOP White House hopeful Mitt Romney, the subject of housing remains an extremely sensitive one, given that housing, or more precisely, the collapse of the housing market, has largely been responsible for much of the last five years of economic pain.

Wiggin suggests that Obama might prefer that the real estate market, whose imbalances sparked the financial crisis, to remain a ghost issue because of a lackluster record at combating the foreclosure epidemic.

Romney, on the other hand, says Wiggin, might like to steer clear of the topic because a hard stance on housing could alienate voters whom he needs to win.

The respective positions of both presidential have tended to leave federal housing officials largely out of view this election season, and most are probably just as happy to stay there.

“Some of the most pressing housing policy issues that need to be resolved have to do with the future of Fannie Mae and Freddie Mac,” Wiggin quotes observer, Jed Kolko, chief economist for listing service Trulia saying. “And that doesn’t work easily in sound bites.”

During Obama’s tenure, Wiggin writes, around 4 million people have lost their homes to foreclosure and 9 million have been served foreclosure notices. There are alternatives that can save homeowners from foreclosure, but federal relief programs that were designed to foster them haven’t fixed the problem.

“Obama’s major housing initiatives have fallen short of expectations, and so Obama doesn’t have big victories to point to,” said Kolko.

Partly for this reason, the fate of Fannie and Freddie is a subject that Romney isn’t too keen on bringing up either, said Mark Calabria, director of Financial Regulation Studies at the Cato Institute, in Wiggin’s piece.

The Republican nominee has said that he believes in reeling in government involvement in the housing market. He even commented at a private fundraiser that he might abolish the Department of Housing and Urban Development. But broadcasting an ambition to dismantle government support of the mortgage market could turn off a wide swath of voters whose businesses depend on the liquidity provided by government muscle.

Clearly, the policy levers that once helped propel housing as an economic force capable of leading the economy out of a recession are now proving ineffective in helping Obama. And at the same the time, they are risky symbol of public policy contradiction for Romney.

Read the full story of Wiggin’s assessment and why its unlikely either candidate was expected to touch the housing issue in last night’s debate, or is likely to in future debates.