Whoever wins the presidential election might feel more like the loser when he realizes what lies ahead for the US economy.

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Slowing earnings combined with CEO warnings of trouble ahead and continuing political instability are persuading more economists that the new year will ring in more of the same slow growth for at least the first half.

So while President Barack Obama or Republican challenger Mitt Romney may get a brief moment to bask in victory, greater challenges than winning a political campaign await.

"A combination of budget tightening and the weak external environment should prevent the U.S. recovery from shifting up a gear next year," Andrew Kenningham at Capital Economics said in an analysis. "As a result, unemployment should fall only gradually."

Jobs and housing have been the two most-watched ingredients in gauging the the U.S. economic recovery. (Read More: Pre-Election Jobs Report Shows Some Gain; Rate 7.9%)

Both have shown halting gains, though not enough to inspire confidence that the momentum has shifted permantently in a positive direction.

Political uncertainty in Washington, most notably over the "fiscal cliff" of tax increases and spending cuts to take place in 2013 unless deficit-reduction targets are met, is acting as a further headwind to growth.

As a result, Wall Street is wrapping up a dismal third-quarter earnings season that has featured only a little more than one-third of Standard & Poor's 500 companies beating sales targets, but also a plethora of dour warnings for the conditions ahead.

"Forward guidance has been almost universally weak, with three out of every four companies guiding negatively this reporting period," said Adam Parker, chief market strategist at Morgan Stanley. "As a result, earnings estimates for the S&P 500 continue to be reset lower, with consensus expectations for (the fourth quarter) down 2.3 percent since the beginning of the earnings season."