By Larry Kane

PHILADELPHIA (CBS) — A new poll adds new drama to the race for president, days away from the start of the Republican national convention.

The latest CBS News-Quinnipiac University-New York Times Poll shows a probable dramatic race to the finish line.

In Ohio, a must-win for the Republicans, President Obama holds a clear lead, 50 percent to 44 percent.  The support of women and younger voters is making the difference there.

In Wisconsin, the race is getting closer — Obama 49 percent, Romney 47 percent — thanks in part to hometown favorite Paul Ryan, chosen by Romney as his running mate.

In Florida, the breakdown is currently Obama 49%, Romney 46%.  Romney does well with senior citizens in that state, but the Medicare issue helps Obama there.

These three states are among nine, including Pennsylvania, where the race will be decided.  The GOP convention begins Monday.