For the next six weeks, the Democratic presidential race between Senators Barack Obama and Hillary Clinton will focus on the state of Pennsylvania.  The northeastern state holds its presidential primary on April 22, and VOA National Correspondent Jim Malone has a look at the strategy for both campaigns from Washington.

Barack Obama continues to lead in the delegate count for the Democratic nomination, but Hillary Clinton's victories in the large states of Texas and Ohio have propelled her back into the race.

Clinton has had some success in raising questions about Obama's readiness to be president and commander and chief, and it is likely she will continue that line of attack in the weeks to come.

"Senator McCain will bring a lifetime of experience to the campaign," Clinton said. "I will bring a lifetime of experience, and Senator Obama will bring a speech that he gave in 2002.  I think that is a significant difference."

Public-opinion polls give Clinton the edge in Pennsylvania, though recent surveys show Obama cutting into her advantage.

Pennsylvania is similar to Ohio in its demographic makeup, with lots of working class voters and women who have tended to support Clinton over Obama in most of the other Democratic caucuses and primaries.

Stuart Rothenberg publishes a political newsletter in Washington and was a guest on VOA's Encounter program:

"You have to understand that Senator Clinton has been performing much better among certain kinds of voters, Latino voters, older voters, women voters and downscale voters, that is very partisan Democrats who have come from less affluent families and have less formal education.  Senator Obama has been doing very well with independents, with younger voters, with, of course, African-Americans and with upscale voters, high education, high income voters," Rothenberg said.

Clinton hopes to raise enough questions about Obama and his experience that even though he leads in the delegate count, some of the so-called super delegates may be drawn to support her at the Democrat's national nominating convention in August.

Super delegates are party activists and elected Democratic officials who attend the convention as uncommitted delegates, and can decide to support whomever they want.

In recent days, Obama has fired back at Clinton's claims about his experience, and continues to cite her initial support of the Iraq war as a key point of difference between the two of them.

"I believe I offer a clean break from the policies of George Bush, because Senator Clinton went along with George Bush on the war in Iraq," Obama said. "Senator Clinton went along with George Bush on her willingness to try to saber-rattle when it came to Iran."

Obama will be targeting super delegates in his strategy as well.  Obama is expected to maintain his lead in the delegate count through the end of the primary season in June.  But he will need help from some of the super delegates at the convention to give him enough additional votes to secure the party nomination.

Political expert John Fortier of the American Enterprise Institute is keeping a close eye on the battle for uncommitted super delegates.

"If the super delegates provide a little bit extra margin needed to get over the top, I do not think that is controversial in itself, and it has happened in the past," Fortier said. "The controversial scenario is that the candidates are relatively close and the candidate who is behind in pledged delegates gets more super delegates and throws him or herself over the top.  And that is the scenario some people speculate for Hillary Clinton."

While Clinton has re-energized her campaign in recent weeks, many experts note public-opinion polls that suggest Obama would be the stronger general election candidate against Republican John McCain.

Analyst Stuart Rothenberg expects Obama to emphasize this point in the weeks ahead.  

"I did want to raise one problem that I think she has in Pennsylvania and from now on, which is this issue of electability," Rothenberg said. "If you look at all the national polls, she does not run as well against Senator McCain as Barack Obama does."

Uncommitted super delegates like Senator Bob Casey of Pennsylvania will be watching the campaign unfold in the weeks to come.  Casey told MSNBC television that he is concerned about pulling the Democratic Party together once the bruising nomination battle between Obama and Clinton is settled.

"I think our nominee has a chance not just to win, but to win with a mandate," Casey said. "But you cannot win with a mandate if you do not bring the sides together.  So we are looking forward to a continuing vigorous debate, but I think we are going to have to work hard on unity."

Democrats will not have much time to unify the party after their national convention in late August.  In contrast, the presumptive Republican nominee, John McCain, has begun that task with months to go until the Republicans formally ratify him as their candidate at their national convention in early September.