U.S. Democratic presidential candidate Barack Obama has managed to narrow his rival Hillary Rodham Clinton's lead in Pennsylvania, the next key state to hold the primary, according to a poll released on Wednesday.
The poll conducted by the Quinnipiac University from March 24 to 31 shows that Clinton beat Obama by 50 percent to 41 percent in the state, eroding from two-digit-percentage lead last month.
The poll also shows a large split among the whites and blacks in the state with Clinton winning nearly 60 percent of white Democrats while Obama drawing 75 percent of black voters.
The primary set on April 22 is considered as a key test for Clinton to have enough momentum to seek the majority of undecided Superdelegates before the party's national nomination convention. For Obama, it is a crucial opportunity to show his capability to carry a big state.
The poll was taken after Obama was endorsed by the state's popular Democratic senator, Bob Casey, but the poll shows it had no real impact on voters' preference.
The Illinois Senator pocketed another two endorsement by Wyoming Governor Dave Freudenthal, a Democratic "Superdelegates" free to vote for either candidate, and Lee Hamilton, one of the party's most respected foreign policy expert.
Freudenthal, whose state was swept by Obama in March 8 caucuses, said in a statement that Obama is the Democratic candidate "with the openness, honesty and skill to end this vicious cycle of business as usual."
As the vice chairman of the commission that investigated the September 11 attacks of 2001 and co-chair of the Iraq Study Group, Hamilton was widely respected for his foreign affairs experience.
"He will strengthen our ability to use all tools of American power and relentlessly promote the American values of freedom and justice for all people," he said of Obama in a statement.