In early April I wrote that the most likely VP picks were Rep. Paul Ryan (R-Wis.), Sen. Rob Portman (R-Ohio) and Virginia Gov. Bob McDonnell. I suggested then that readiness to be president, smarts coupled with seasoning and some personal chemistry with Romney would be key. Of Sen. Marco Rubio I wrote, “Even if he wanted the spot, Sen. Marco Rubio (R-Fla.) would be lower on the list than a candidate who embodies Romney’s preference for experience.”

Today the media are all agog that Rubio is reportedly not being vetted.

It has been rather obvious for some time that Rubio and Romney weren’t a good match. As President Obama appears more and more clueless about how to fix the economy and lead on the international stage ,it becomes all the more important for the GOP ticket to embody maturity and experience. To be blunt, Rubio’s too new on the national scene.

Moreover, in his definitive statements (“I will not be VP”) he left zero wiggle room to consider a VP slot. Unlike the faux modesty of those interested in the post (I am sure Gov Romney has better choices or I’m not even thinking about it) Rubio suggested he’d be unwilling to face the burning hot light of scrutiny. His closest advisers months ago confided they thought he had a long future and might be better served waiting this election out.

Conservatives should not be glum. Rubio has many, many presidential elections ahead of him. He’ll remain a powerful advocate for Romney and an important voice in the party. It just isn’t his time.

As for those still in consideration, my head says Portman (solid executive experience, from a critical state, won’t outshine the top of the ticket, international experience as the U.S. trade representative). My heart says Ryan (conservative wonk with Tea Party street cred, an unparalleled ability to make the economic case against the president, an accessible Midwesterner who help in Wisconsin). Ryan is the gutsier choice. Picking him would be a sign of unflagging faith in a message centered on free markets and entitlement reform. But with Ryan there might also be more to gain with a dynamic salesman for the message focus on the contrast between the “opportunity society” and the “entitlement society.” It would also be some sweet karma to put Ryan on the ticket: The president who has consistently evaded responsible action on entitlement and fiscal reform up against the congressman who has been the model of political courage.

But stay tuned. This is a case in which we may know who isn’t going to be the pick, but no one outside the Romney campaign’s tight circle knows who it will be.