Who else could it have been? Jindal and Paul Ryan have already done it, Rand Paul’s probably still too close to the rEVOLution for Republican leaders to be comfortable with him in a spot like this, and Chris Christie would just end up talking about how terrific Obama’s speech was. Half the reason party leaders are pushing amnesty, I’m convinced, is because Rubio’s that good in front of a mic and this issue gives him access to lots and lots of microphones. If, as McCain bluntly concedes, immigration reform is all about earning goodwill from Latino voters, then of course the party’s biggest Latino star gets this platform. And in case you’re hazy on who the target audience here is, Rubio will deliver his address in English and Spanish:

“Marco Rubio is one of our party’s most dynamic and inspiring leaders. He carries our party’s banner of freedom, opportunity and prosperity in a way few others can. His family’s story is a testament to the promise and greatness of America,” said Speaker Boehner. “He’ll deliver a GOP address that speaks from the heart to the hopes and dreams of the middle class; to our party’s commitment to life and liberty; and to the unlimited potential of America when government is limited and effective.”

“Marco Rubio embodies the optimism that lies at the heart of the Republican vision for America. On Tuesday, he will contrast the Republican approach to the challenges we face with President Obama’s vision of an ever-bigger government and the higher taxes that would be needed to pay for it,” said Senator McConnell. “Marco’s own experience as the child of immigrants has always informed his belief in limited government and free enterprise, which is why he has helped lead the fight against out-of-control spending and job-destroying tax hikes that continue to hold our economy back and stifle opportunity for millions. He was a natural choice to deliver the Republicans’ alternative to the administration’s reliance on government and debt.”

“I’m honored to have this opportunity to discuss how limited government and free enterprise have helped make my family’s dreams come true in America,” said Senator Rubio. “Limited government and free enterprise are the very foundation of what makes America special and separates us from the world, particularly through our strong middle class. I look forward to laying out the Republican case of how our ideas can help people close the gap between their dreams and the opportunities to realize them.”

Immigration will be mentioned in the speech, but an aide to Rubio tells CNN that that won’t be the focus. The focus, wisely, is on convincing middle-class voters more broadly that they’ll do better with the GOP’s limited government agenda. Rubio told Rush Limbaugh last week he’s confident that he (not necessarily the party, but he himself) can sell that idea. With America having just reelected the Sixteen Trillion Dollar Man, I’m pretty confident that no one can. Prove this eeyore wrong, Marco. Please.

Exit question: Between this and his influence over the fate of immigration reform, is Rubio the new de facto leader of the GOP?