Mitt Romney is not known as a gambling man.  When choosing a running mate, many observers expected Romney to make the safest, most cautious choice — most likely Ohio Sen. Rob Portman.*  By instead choosing Rep. Paul Ryan, Romney is sending a clear signal that he intends to run a more daring and more ideologically vigorous campaign than he has run up to this point.  And in that sense, Romney has now become a gambling man.

Although Romney had embraced the Ryan budget plan, he has now embraced its author, too — and in the process moved the issue of entitlement reform and controls on federal spending to the top of the Romney campaign agenda.  It wasn’t in such a prominent position before.

Romney’s gamble is that in the midst of an economic downturn, voters are ready to accept Ryan’s prescription for fixing the federal budget, in particular his proposals for reforming Medicare.  Romney and Ryan are right that major changes need to be made, and at some point the voting public will accept that view, too.  That day is coming.  The question is whether it will arrive by November 6.

Of course Team Obama says it is delighted with Romney’s choice, because they believe they can destroy Ryan’s plan, and in the process the Romney-Ryan candidacy.  And it seems likely that at the very least choosing Ryan has made winning Florida a little harder for Romney — and if Romney doesn’t win Florida, he doesn’t become president.  What Democrats are overlooking is that Ryan is a truly formidable figure.  He not only knows his stuff, he is able to communicate his ideas in a persuasive and appealing way.  There’s a very good chance voters will like him.  Democrats love to portray Republicans as angry.  They won’t be able to do that with Ryan, who doesn’t give off even a hint of anger.

But the fact remains that there has never before been a national debate about entitlements like the one that is coming in this presidential campaign.  Mitt Romney has decided it’s time for that debate, and that he can win it.  That’s the biggest bet of his candidacy, by a long shot.

*Observers like me — see here.