CNN has the story here.
That tells you what kind of president Santorum would have made: A president who, like Rubio, would have settled for the Gang of Eight amnesty bill because it was all he could get at the time.
Rush Limbaugh can protest all he wants about Rubio giving up his Senate seat as a sign he's not committed to time-serving the establishment. The truth is as president Rubio would disappoint on illegal immigration to the point of destroying the Republican Party and the country as we have known it.
Establishment support for Rubio will now accelerate. The conservative vote will be split between Cruz and Trump.
Rubio will win the nomination like Romney did, through attrition on the right as neither Trump nor Cruz wins enough delegates to secure the nomination just as Santorum and Gingrich and Paul did not.
In this election, Ted Cruz, the illegal immigration flip-flopper, will be Donald Trump's spoiler.
In the immortal words of Mickey Kaus, Cruz is just in it for Cruz.