Rick Santorum’s run for the GOP presidential nomination is over. In his speech, Santorum thanked supporters in Texas for working to make it a winner-take-all primary "because they want to make sure that we have the best opportunity to, for Texas and for conservatives to have a voice in this primary."

In an email to supporters following his speech, his campaign echoed that sentiment.

"Our good friends in Texas have been working non-stop to make sure that they have a say in the choice of our nominee, but without the state changing its delegate allocation to winner-take-all, I do not see a path forward that does not risk our shared objective of defeating Barack Obama in November. I want to thank them for their valiant efforts," Santorum writes.

Mitt Romney congratulated Santorum on his campaign and called him "an able and worthy competitor." The Ron Paul campaign said it will continue to fight–and will not drop out before the Republican Convention in Tampa.

"Congratulations to Senator Santorum on running such a spirited campaign. Dr. Paul is now the last – and real – conservative alternative to Mitt Romney. We plan to continue running hard, secure delegates, and press the fight for limited, constitutional government in Tampa."