New Jersey Governor Chris Christie has decided not to seek the US presidency in 2012, disappointing many who are unsatisfied with the current crop of Republican candidates, reports said. Christie, who was seen as a credible opponent for President Barack Obama in November 2012 due to his strong governorship of a traditionally Democratic state, was to make his announcement on Tuesday at 1:00 pm (1700 GMT). But the 49-year-old rising star in the Republican Party appeared to have put out word in advance that he would not be running, with US media including the New York Times and the Washington Post citing aides to that effect. Christie had been seen as the last realistic option for Republicans seeking to shake up a race so far dominated by former Massachusetts governor Mitt Romney and Texas Governor Rick Perry. Obama is seen as increasingly vulnerable because of the country\'s sputtering economic recovery and stubbornly high unemployment. Media speculation will continue to swirl over Tea Party darling Sarah Palin, the losing vice presidential candidate in 2008, but barring any last-minute surprises the field now seems set for the Republican primaries. Perry\'s popularity has plummeted following some weak debate showings as former pizza company executive Herman Cain has risen to draw even him, a new poll showed Tuesday. The Washington Post/ABC News poll of 2012 Republican White House candidates showed Romney in the lead, with 25 percent support for a second straight month. Perry meanwhile dropped 13 points and Cain rose 12 points since early September to tie at 16 percent. Cain, the former chief executive of Godfather\'s Pizza, won an upset victory in last month\'s Florida straw poll, a key test vote. Christie has already repeatedly scoffed at the idea of entering the 2012 race, but calls for him to reconsider grew in recent days as Perry\'s campaign faltered. Growing numbers of Republicans had identified Christie, a political newcomer who won plaudits for tough leadership in deficit-ridden New Jersey, as an exciting alternative. If he had jumped in, Christie\'s late entry would have left him with an uphill battle to make a mark in early-voting primary states where other candidates have already been courting at length. That task was made harder still on Monday when South Carolina Republicans announced they would hold their first-in-the-south presidential primary on January 21 in a bid to outdo a similar move by Florida. Florida decided last month to move up the vital battleground\'s presidential primary date to January 31, sowing chaos in the political calendar. An early primary or caucus is thought to give a state more influence in shaping the eventual party nominee, giving the winners more media coverage needed to help raise money and building momentum among core party supporters. In a closely watched speech at the Reagan Library in California, Christie last week seemed to anoint himself as the new embodiment of Ronald Reagan, a revered figure among Republicans as they seek to make Obama a one-term president. Launching a bitter attack on what he said was Obama\'s failure to lead, Christie said his own record in his first year as governor of New Jersey showed how Washington could be run. \"The executive branch has not stood by and waited for others to go first,\" he thundered, branding Obama \"a bystander in the Oval Office\" and \"a president who once talked about the courage of his convictions but still has not found the courage to lead.\" Sounding more than a little presidential, Christie also envisioned how the United States could \"sustain the leadership role of the world\" and ensure \"a second American century.\"