NEW YORK (TheStreet) -- In 2008, when the country was in the depths of the financial crisis, the U.S. Treasury put wounded institutions Fannie Mae (FNMA) and Freddie Mac (FMCC) into a financial limbo called "conservatorship." At this point, both President Obama and the slew of candidates seeking to succeed him may be avoiding this highly partisan topic, but American investors shouldn't ignore it, because the fate of these entities directly affects their portfolios, said Bethany McLean, author of the recently published book Shaky Ground: The Strange Saga of the U.S. Mortgage Giants.

"The mortgage-backed securities that they issue, it is debt backed by the mortgages of Americans and there is about $5 trillion of it outstanding today," said McLean. "It moves through the global capital markets like water. It's everywhere."

McLean was also the co-author of the bestseller The Smartest Guys in the Room: The Amazing Rise and Scandalous Fall of Enron with her Fortune magazine colleague Peter Elkind. And she co-authored All the Devils are Here: The Hidden History of the Financial Crisis along with New York Times columnist Joe Nocera.

McLean said that government-sponsored entities Fannie and Freddie have become political pariahs because capitalists and free-market purists don't want the government playing a role in thehousing market. Some claim that the two lenders caused the housing crisis. She added that Fannie and Freddie executives have historically been richly rewarded, turning the companies into political patronage footballs.

Simply put, McLean said, Fannie and Freddie's decisions to dive into the subprime mortgage world at exactly the wrong time doomed them to bankruptcy. Then-Treasury Secretary Hank Paulson directed the government to take over the companies to prevent them from further destabilizing the global economy.

Since their multi-billion dollar rescue by Uncle Sam, the government-sponsored entities have returned to profitability, and the U.S. Treasury has been the beneficiary of Fannie and Freddie's good fortunes. Pershing Square Capital Management's Bill Ackman and other hedge fund managers, however, are suing the government for allegedly stealing Fannie and Freddie from shareholders without just compensation. 

As for why the many 2016 presidential candidates are not talking about the government-sponsored entities, and how a pair of companies can have over $5 trillion of debt in the market while operating on "no capital," McLean said it's a great example of political dysfunction in the face of a complicated problem.

"It does not lend itself to an easy solution. Politicians want their talking points as simple as 'Get rid of them!' and as soon as they learn a little more about the situation, they think 'Oh, it's complicated,' and so they stop talking about it," said McLean.