Former President Obama cautioned 2020 Democratic candidates not to move too far to the left, as messages of sweeping societal and government transformations risk turning off the party's moderate base, according to the New York Times.

"Even as we push the envelope and we are bold in our vision, we also have to be rooted in reality," said Obama - who told a room of wealthy liberal donors: "Even as we push the envelope and we are bold in our vision we also have to be rooted in reality."

"The average American doesn’t think we have to completely tear down the system and remake it."

Obama joins House Speaker Nancy Pelosi, former Florida Senator Bill Nelson, and other moderate Democrats in his implicit warning over plans by Sens. Bernie Sanders (I-VT) and Elizabeth Warren (D-MA) who have called for a "political revolution" and "big structural change" with ideas that would eliminate private health insurance and place a moratorium on deportations according to The Hill.

The comments marked an extraordinary entrance into the primary contest by the former president, who has been careful to avoid even the appearance of influencing the direction of the race. His remarks offered an implicit critique of Senators Bernie Sanders and Elizabeth Warren, who have urged voters to embrace “political revolution” and “big, structural change,” as well as proposals once widely considered to be left to the liberal fringes of the party, including court packing and decriminalizing illegal border crossings. -NYT

"I don't think we should be deluded into thinking that the resistance to certain approaches to things is simply because voters haven't heard a bold enough proposal and if they hear something as bold as possible then immediately that's going to activate them," added Obama. "There are a lot of persuadable voters and there are a lot of Democrats out there who just want to see things make sense. They just don’t want to see crazy stuff. They want to see things a little more fair, they want to see things a little more just. And how we approach that I think will be important."

In April, the former president said "One of the things I do worry about sometimes among progressives in the United States — maybe it’s true here as well — is a certain kind of rigidity where we say, 'Uh, I’m sorry, this is how it’s going to be,' and then we start sometimes creating what’s called a 'circular firing squad,' where you start shooting at your allies because one of them has strayed from purity on the issues," adding "And when that happens, typically the overall effort and movement weakens."

In early November, Pelosi suggested that 2020 Democrats may strike out against Trump with ultra-liberal policies that may fire up coastal leftists, but may not go over well elsewhere.

"What works in San Francisco does not necessarily work in Michigan,"Pelosi said in a wide-ranging interview with Bloomberg. "What works in Michigan works in San Francisco — talking about workers’ rights and sharing prosperity."

Bill Nelson, meanwhile, also said earlier this month that if Warren or Sanders become the party's nominee in 2020 that Democrats would effectively be ceding Florida to Trump.

"The answer is yes," said Nelson - a Biden supporter who narrowly lost his re-election in 2018. "I say this with the greatest respect and admiration and friendship for those other senators who embrace Medicare for All. But the hard reality is, it is going to be a stretch too far for the Democrat candidate."

And while Obama is now cautioning 2020 progressives against straying too far left, he's still not endorsing his former VP Joe Biden, the moderate Democratic frontrunner.