President Obama said today he is expediting approval of the southern end of the Keystone XL oil pipeline -- from Oklahoma to the Gulf Coast of Texas -- and he criticized Republicans for turning an energy and environmental issue into a political one.

"The southern leg of it, we're making a priority," Obama told workers during an 11-minute speech in Cushing, Okla., the terminus of the pipeline project.

House Speaker John Boehner and other Republicans called Obama's permit announcement meaningless because the southern end of the project is due to start construction in June anyway. And they continued to criticize Obama for blocking the northern part of Keystone, connecting the U.S. to oil supplies in Canada.

Boehner spokesman Brendan Buck compared Obama's announcement to "the governor holding a press conference to renew my driver's license -- except this announcement still leaves American energy and jobs behind."

The proposed Keystone pipeline has become a symbol of the political struggle over gas prices between Obama and the Republicans.

Obama's speech began the second and final day of a tour in which the president is promoting his "all-of-the-above" energy strategy, including new energy sources as well as increased domestic oil production.

He delivers another energy speech later today at Ohio State University in Columbus.

Oil production is indeed up, Obama told Oklahoma residents: "Anyone who says that we're somehow suppressing domestic oil production isn't paying attention.

"We are drilling all over the place, right now," Obama said.

But drilling alone will not bring down prices at pump, he added, and that requires government help for developing alternatives.

In discussing the Keystone pipeline, Obama said that part of the northern route potentially threatens water supplies in Nebraska, and must still be reviewed.

Republican presidential candidates have also jumped on the Keystone issue, calling it an example of an Obama regulation that is driving up gas prices.

"Apparently the slipping poll numbers have convinced him to announce the lower half of that pipeline," Mitt Romney said. "If we can get his poll numbers just a little lower we may be able to get the other side too. So let's get that job done."