Democrats are expressing growing alarm about President Obama’s re-election prospects and, in interviews, are openly acknowledging anxiety about the White House’s ability to strengthen the president’s standing over the next 14 months.

Elected officials and party leaders at all levels said their worries have intensified as the economy has displayed new signs of weakness. They said the likelihood of a highly competitive 2012 race is increasing as the Republican field, once dismissed by many Democrats as too inexperienced and conservative to pose a serious threat, has started narrowing to two leading candidates, Mitt Romney and Rick Perry, who have executive experience and messages built around job creation…

But a survey of two dozen Democratic officials found a palpable sense of concern that transcended a single week of ups and downs. The conversations signaled a change in mood from only a few months ago, when Democrats widely believed that Mr. Obama’s path to re-election, while challenging, was secure.