Obama leads Romney in three key states, poll shows

— -- President Barack Obama leads Mitt Romney in the three critical swing states of Florida, Ohio and Pennsylvania, a Quinnipiac University Swing State Poll released Wednesday shows.

The poll shows Obama with a tight 4-point edge in Florida, a healthy 9 points in Ohio and 6 points in Pennsylvania.

That's a change from a Quinnipiac University poll on May 3 that showed Obama with an 8-point lead in Pennsylvania with Florida and Ohio too close to call.

Here's the state-by-state breakdown from the latest poll:

• Florida: Obama edges Romney 45 — 41 percent;
• Ohio: Obama over Romney 47 — 38 percent;
• Pennsylvania: Obama tops Romney 45 — 39 percent.

No one has won the White House since 1960 without taking at least two of these three states.

"President Barack Obama has decent margins over Gov. Mitt Romney in Ohio and Pennsylvania and a smaller advantage in Florida.  If he can keep those leads in all three of these key swing states through election day he would be virtually assured of re-election," said Peter A. Brown, assistant director of the Quinnipiac University Polling Institute. "Of course the election is more than four months away, which is a lifetime in politics."

Brown noted that Obama's margin is built on his big lead among women, younger voters and African-Americans.  He also said Obama, on the heels of his order preventing deportation of some younger illegal immigrants, holds a big lead among Hispanic voters.

The poll, conducted June 19 — 25, has a margin of error of plus or minus 2.8 percentage points in each state.