Image credit: Gerald Herbert/AP Photo

He took Arizona and eked out a win in Michigan but there are still three things Mitt Romney needs to do in order to become the Republican nominee, Matt Dowd  said on "GMA."

"First he has got to win conservative votes. Second he has got to put together a winning streak. Nobody has put together a winning streak in this," Dowd, an ABC News contributor, said.

He's right on both counts. Last night Romney split the conservative vote. The "very conservative" voters went for Rick Santorum while the "somewhat conservative" group supported Romney.

And as Dowd pointed out it has been a momentum-proof campaign. Romney won New Hampshire, but lost South Carolina. He took Florida and Nevada but came in second to Rick Santorum in Colorado, Minnesota and Missouri. A trend the Romney campaign needs to break before Tampa.

And the third thing Romney has to do:

"He has got to be able to unite the party behind a positive message. He has not been able to do that yet," Dowd said. "And I think those three questions he has to answer before you sort of put the mantle on him and say he is the nominee."

The former Massachusetts governor has a tough road looking at the Super Tuesday map. 437 delegates are up for grabs in 10 states. Romney will do fine in Vermont and Massachusetts, but he is behind in the southern states of Tennessee, George and Oklahoma.

Then there is the all important battleground state of Ohio: A must-win for Santorum if he wants to stay in this race.

"We're going to go from the Wolverine state to the Buckeye state and that's where I think the battle will ultimately be decided whether or not this nomination is closed down and Mitt's got it," Dowd said.

"[Santorum] absolutely has to win Ohio and he has to win some of those other small caucuses," he said.

Watch my interview here: