By Larry Kane

PHILADELPHIA (CBS) - If the election were held today it would be a nail biter.

The nationwide CBS survey has a dead heat between President Barack Obama and Republican candidate Mitt Romney — 46-percent each.

In March, the president had a three-point lead, in February a six-point lead. Now it’s even.

There are some interesting figures for Romney. While Democratic voters are enthusiastic about Obama, only 33-percent of Republican voters are enthusiastic about Romney while 40-percent support him with reservations, but they do support him.