Clinton lead narrows in Pennsylvania

A new round of polls brings mixed results today for Hillary Clinton.

A Quinnipiac University survey shows that her lead in must-win Pennsylvania has shrunk into the single digits -- to 50 percent to 41 percent over Barack Obama -- three weeks before the April 22 primary. She held a 12-percentage-point edge in mid-March.

Clinton continues to lead among white voters, women, and older voters, while Obama has an edge among black voters and younger voters. The two are running even among men. The poll was conducted March 24-31 and has a margin of sampling error of plus or minus 2.5 percentage points.

Both candidates are campaigning again in Pennsylvania today. At an economic summit in Pittsburgh, Clinton plans to highlight her proposal for $7 billion a year in tax incentives to encourage US companies not to ship jobs overseas. Obama plans events in Philadelphia, Wallingford, and West Chester. In a speech to the Pennsylvania AFL-CIO, Obama will pledge to renegotiate the North American Freed Trade Agreement, invest in "green economy" jobs, and work for universal healthcare.

Other Quinnipiac polls suggest that Clinton would fare better against presumptive Republican nominee John McCain in Pennsylvania as well as two other key battleground states, Florida and Ohio, that a Democratic almost certainly needs to win in November to win the White House.

In Pennsylvania, Clinton leads McCain 48 percent to 40 percent, while Obama leads McCain 43 percent to 39 percent.

In Florida, Clinton leads McCain 44 percent to 42 percent, while McCain leads Obama 46 percent to 37 percent.

In Ohio, Clinton has a 48 percent to 39 percent edge over McCain, while Obama narrowly leads 43 percent to 42 percent.

For Clinton, electability is one of her most important arguments to make to Democratic superdelegates, who will likely decide the nominee.