Over the weekend, Marco Rubio was asked whether, at age 42 and just under four years into his Senate service, he thought he was ready to be president. "I do," Rubio responded. "I’ll be 43 this month, but the other thing that perhaps people don’t realize — I’ve served now in public office for the better part of 14 years."

U.S. President Barack Obama listens to remarks by Uruguay's President Jose Mujica before their meeting in the Oval Office in Washington May 12, 2014. REUTERS/Jonathan Ernst (UNITED STATES - Tags: POLITICS)

Prior to 2008, Rubio's response might have elicited eye rolls from the political class -- Democrat and Republican. Today, living in the Obama era, it drew barely a ripple of outrage. (Make no mistake: There were eyerolls -- just not as many as there might have been a few years back.)

Of all of the ways President Obama has changed politics, one of the most under appreciated is that he has drastically altered the career trajectory -- or at least the calculation of career trajectory -- for ambitious young politicians around the country. Obama's story is now well known to just about anyone who follows politics with even a passing interest: Six Eight years in the state Senate, two years in the U.S. Senate before he started running for president and elected to the office at the ripe young age of 47.

"Obama set the bar low from a qualification standpoint," said Scott Howell, a Republican political consultant based in Dallas. "He proved that if you can look presidential and also have an ability to communicate effectively, you can be successful.  His success makes it much easier for a candidate like Rubio to be taken seriously and...be successful."

A look around at the potential 2016 field on the Republican side reveals just how impactful Obama's rapid rise has been.  Ted Cruz, 43, was elected to the Senate in 2012 but is already quite clearly positioning himself to run for president in 2016. Rand Paul, elected to the Senate in 2010 after never having held political office before, is a near-certain presidential candidate. (Paul is 51 years old.) Wisconsin Gov. Scott Walker is 46 years old. Louisiana Gov. Bobby Jindal is 42. (The relative youth of the Republican field will stand in stark opposition -- both in terms of age and experience -- to Hillary Rodham Clinton, the likely Democratic nominee. Clinton will be 69 years old on election day 2016 and has spent the last two decades-plus in the national public spotlight.)

Simply because Obama made it more acceptable to run for president as a younger and less experienced pol doesn't mean that's a good thing for people like Rubio, Cruz and Paul, according to former Bush White House spokesman Ari Fleischer.

"One issue Senators Paul and Rubio will confront is whether after the Obama experience, our nation is ready to elect someone without significant experience," said Fleischer. "Being an outsider has its advantages, but it also helps to know how to get things done.  It's not a show stopper, but they'll need to convey they have the knowledge and gravitas to lead and get results." (Politico's Manu Raju explored this idea more deeply in a story that ran earlier this week.)

What Rubio -- as well as the other young candidates -- will try to do is differentiate their experiences from those that Obama had before coming into the presidency.

On Sunday, Rubio was quick to note that he had served in elected office for more than a decade (not sure that's such a good thing in this political environment) and that he had been the Speaker of the state House before being elected to the Senate.  "Rubio is more ready than Obama was," said longtime GOP hand Charlie Black. "Obama did nothing in the Senate except spout general rhetoric and campaign for president. Rubio has been a serious legislator." ("Serious", of course, lies in the eye of the beholder; Black noted Rubio's role on immigration reform, a piece of legislation that has evoked strong negative reaction to the Florida Senator from within the GOP base.)

Both Paul and Cruz will likely focus on their lack of political experience as a positive -- given how broken the political process is and how much people dislike Washington. In so doing, of course, they will be -- whether consciously or not -- taking a page from the Obama 2008 playbook. Remember these lines from Obama's announcement speech in February 2007?

I recognize there is a certain presumptuousness -- a certain audacity -- to this announcement. I know I haven't spent a lot of time learning the ways of Washington. But I've been there long enough to know that the ways of Washington must change.

No one now questions the viability of people like Rubio, Cruz and Paul -- even if they do wonder if their relative age and inexperience is an asset or a liability in the eyes of voters.  Those candidates have President Obama to thank for their now-assumed viability -- although they may also have him to blame if their relatively thin political resumes come back to bite them in the race for the nation's top office.