( CNN ) -- All of the candidates in the presidential campaign agree the 2012 election will revolve around the economy . Although there are signs that conditions are slightly improving , the high unemployment rate and the depressed housing market are causing immense anxiety among American voters . As a result , most of the political debate has centered on how the nation will rebound from the steep 2007-09 recession and anemic recovery that has afflicted the nation throughout President Barack Obama 's term in the White House . Republicans and Democrats have tried to walk a political high wire as the release of new economic data continually changes the playing field . Mitt Romney , for instance , fell into a trap when he admitted that there were signs the economy was improving , a statement that caused many Republicans to grumble about their front-runner handing Democrats the key issue . Meanwhile , Obama 's optimism has often been undercut with data showing that the situation is still bad . With all the attention that has been given to short-term economic recovery , however , politicians in both parties have generally avoided the types of long-term structural challenges that are really at the heart of national anxiety and which greatly threaten America 's ability to compete with China and other rising economic powers . The first problem has been the exodus of good jobs to other countries . In one of the most troubling developments of recent decades , many types of industrial jobs have been shipped overseas . And by and large , they wo n't be returning . Numerous companies have built facilities in other countries where labor costs are lower , workplace laws are lax or nonexistent and other kinds of regulations are weak . According to a recent study by the Information Technology and Innovation Foundation , the United States lost 5.7 million manufacturing jobs in the 2000s . If these trends continue , the tight labor market will become the new normal . The chances for high school and college graduates to land solid jobs in the U.S. will diminish , as has already been the case for many working Americans who have watched the factories shut down . Another chronic challenge facing the U.S. is the rising level of inequality in the United States . The gap between the rich and poor has grown dramatically since the 1970s . A troubling trend that has lasted for decades has been that the average income of the top 5 % has risen while the average income of the rest of the nation has fallen . The number of Americans in the ranks of the middle class has thinned . The income supports upon which workers depended have diminished , both those provided by government and by private employers . More Americans find themselves squeezed lower onto the lower rungs of the economic ladder . As many commentators have noted , there are a number of causes for this growing gap , including public policy . Without the ability of the government and private markets to reverse this trend , the U.S. will not be able to sustain the kind of vibrant middle class -- which in the 1940s and 1950s was attainable by more and more Americans -- that has been the engine behind the American dream . The final challenge is an urban crisis that has decimated pockets of America . As Thomas Sugrue showed in his award-winning book , `` The Origins of the Urban Crisis , '' the breakdown of the cities began in the 1940s and 1950s as racist employment practices and real estate markets hampered the ability of African-Americans to get good jobs or relocate into better neighborhoods . The problems accelerated as jobs continued to move into the suburbs ( before moving overseas ) . Rioting in the 1960s further devastated these communities . The result of the urban crisis has been that multiple generations of inner-city residents have lived with little hope for a better future and have struggled to make ends meet , trying to survive on streets that are ridden by crime and drugs . Many black leaders have been deeply disappointed that Obama , the first African-American occupant of the White House , has not done much to address these issues . Although Republican Rick Santorum recently proposed tax cuts to lure business into these areas , there is little evidence that such a change in policy would do much to reverse decades of decay . These are not the kinds of issues that politicians like to talk about in their campaigns . As opposed to temporary recessions , these quasi-permanent structural challenges have been decades in the making and will require wrenching policy choices as well as dramatic market developments to resolve . If our political leaders do n't address these issues that underlie the concerns of the nation , it will become ever more difficult to re-create the vibrant economic conditions that existed during the `` American Century '' when grand expectations about the future , as the historian James Patterson argued , guided public debate . Then , the nation was strong and the possibilities for growth seemed infinite . Today , even if short-term conditions improve , our economy is far from what it used to be . How to achieve a better future is the debate that we really should be having in 2012 . The opinions expressed in this commentary are solely those of Julian Zelizer .
Candidates agree that the economy is the main issue in the election . Julian Zelizer says they 're ignoring the deeper economic challenge America faces . Good jobs have gone offshore , inequality is growing and urban areas lag , he says . Zelizer : U.S. economic problems are decades in the making and need serious attention .