( CNN ) -- In American politics , there is strength in numbers . When enough people feel a vested interest in the survival of a program , it becomes extraordinarily difficult for opponents to dismantle it . Obamacare , officially the Affordable Care Act , looks like it has just reached a critical tipping point . While the program still faces many challenges and numerous Republicans remained determined to keep attacking , the news that 7 million people have enrolled through the health care exchanges is a big victory for President Barack Obama and his supporters . Medicaid enrollment rose by 3 million people , much of which is a result of ACA as well . Rather than Obamacare being an abstract promise to Americans that will be fulfilled in the distant future , now the Affordable Care Act is a concrete program upon which millions of American voters will be depending . As that number increases , opponents of ACA will be going after the benefits of many millions of Americans -- not just the President . There is a long history of government programs securing their political strength through sheer numbers . Although Social Security remained a problematic and controversial program between 1935 and 1950 -- with some officials wondering whether it would even survive -- by the time that Dwight Eisenhower was President , there were fewer legislators willing to express such doubts . The reason was simple . Democratic and Republican legislators found their districts inhabited by elderly Americans who counted on these government pensions and workers who were paying payroll taxes . This is why legislators would increase benefits every election year . Agricultural supports have been equally strong since being put into place during the Great Depression . As farmers , farms and the entire agricultural industry came to depend on federal government assistance to ensure that prices remained stable , legislators shied away from trying to fix the program . Even legislators who represented urban districts had little interest in angering powerful rural representatives and senators whose constituents would not tolerate anyone tampering with their programs . When Eisenhower 's Secretary of Agriculture Ezra Taft Benson went after the program , Republicans suffered . `` Ezra Taft Benson , '' one reporter said when covering the 1954 midterm elections , `` has become the [ Democrats ' ] fall guy , replacing the tired image of Herbert Hoover . '' In the years before Congress passed Medicare and Medicaid in 1965 , opponents -- including powerful voices in the health insurance industry and the American Medical Association -- railed against the plan as `` socialized medicine '' that would empower the government to make all the decisions doctors had once had control over . But President Lyndon Johnson and the Democratic Congress overcame their opposition to put into place these two major domestic programs . By the 1970s , serious opposition fell away . Doctors were depending on Medicare to fund their patients . Hospitals and states were planning on the Medicaid budget to keep their health systems going . And elderly patients no longer suffered the risk of not being able to seek treatment in their old age . As a result , nobody really wanted to get rid of these programs . Although there were fights to reform Medicare 's regulatory structure and to cut costs since the 1980s , the strength of the programs has been formidable . There has been , thus far , little possibility that either would be scrapped . The same has been true for defense spending . The surge of military contracts in Southern and Western states during the 1940s and 1950s became a staple to the economic success of the Sunbelt . There are many reasons why defense spending is hard to retrench , but most important is the huge number of people who will vote and lobby against you if you take a step in this direction . ACA is now starting to reach this same territory . For this reason alone , it makes sense that Obama is smiling . While the program does not have the tens of millions of people who are in the Medicare or Social Security programs , the numbers are growing . ACA will continue to face political attacks and implementation challenges , but the enrollment level virtually ensures serious debates over repealing ACA are now dead .
More than 7 million people have signed up for Affordable Care Act coverage . Julian Zelizer says that ensures that President Obama 's signature program will endure . As with Medicare and farm subsidies , programs that benefit millions tend to last , he says . Zelizer : Obamacare will face implementation challenges , but talk of repeal is aimless .