No, Winston Churchill did not say, "If you're not a liberal when you're 25, you have no heart. If you're not a conservative by the time you're 35, you have no brain."

And good thing he didn't, or he'd have been completely, terribly, utterly wrong.

For the better part of the last decade, I've been waging war on this misconception. Why? It gives people on the right of the political aisle an excuse to shrug off concerns that the millennial generation is left-leaning in its politics. It offers the appealing illusion that the slow passage of time and setting in of reality is the only ingredient necessary for turning today's naïve little liberals into tomorrow's wise and rational conservatives.

Nonsense. And fresh data from the Pew Research Center underscores the extent to which the kids these days, and their counterparts in "Generation X", are not only not making the hoped-for slow march toward the political right, but drift ever more leftward, even as they age.

The young may lean left today, the old may lean right, but according to Pew's new study of tens of thousands of voters, the last 15 years have only widened the gap. Rather than showing all generations on parallel tracks, gradually evolving toward conservatism and the GOP as time passes, both the millennial generation (roughly: those born in the 1980s and 1990s) and Generation X (the folks sandwiched between millennials and 1964's late Boomers) have gotten more liberal in the last decade.

In the year 2000, the very youngest members of the Baby Boomer crew were in their mid-30s, while the oldest Boomers were mid-50s. That year, the Boomers were a generation divided somewhat equally between the GOP and Democrats. Adding ideology to the mix, some 23 percent considered themselves conservative Republicans, while only 13 percent were liberal Democrats. Fast forward to 2016, and sure enough the Baby Boomers have gotten more conservative, with an increase of eight points, to 31 percent now identifying themselves as conservative GOP-ers.

The Boomers look around and see that their cohort has moved rightward. Therefore, for the Boomers, the faux Churchill line rings true, and they assume everyone will turn out like them.

But that's not quite what's happened to Gen X. Today, the very youngest members of Generation X are … in their mid-30s. Same place in their life cycle as Boomers in the year 2000. Generation X is now raising families, they're well-established in their careers, they're worrying about sending kids to college. They're doing all those things that are supposed to make you wake up and become conservative.

And yet, the big supposed conservative boom has been a bust, with Gen X's share of conservatives having held firm for more than a decade. No fairly-even party divide for these folks, either; instead, Democrats outnumber Republicans among Gen X, 48 to 37.

All of which makes the partisan and ideological breakdown of the millennial generation even more striking. The Boomers got more conservative, Gen X got a little more Democratic, and over the last 10 years, the millennials got more liberal.

They didn't start out that way. When the oldest batch of millennials really first began voting around the mid-2000s, they leaned a little toward the Democrats, looking a lot like the Gen Xers also did at that time. In 2008, the rise of Barack Obama sent a shockwave through the generation, with big growth in the share identifying as Democrats, reaching a full 56 percent during the 2008 election.

What is striking for millennials is less about the partisanship and more about the ideology. It's not just that Democrats have held a consistent advantage over the GOP with this generation (and they have – by massive margins), it's that the proportion calling themselves liberal Democrats has increased substantially since the 2012 election. Millennials are getting older, and yet they aren't moving rightward at all. Like the Gen Xers ahead of them, they're instead more and more likely to decide "liberal" suits them just fine as a label.

It's true that the Baby Boomers (and their parents, the Silent Generation) got more conservative in the last decade. Around the election of Obama in 2008, the share of voters born before 1965 who identify as conservative Republicans took a jump. Major realigning events can reshape coalitions, and change how large groups of people view politics, policy, and the parties.

Maybe President Trump will turn out to be a fabulously successful president who will endear the millennial generation to the right anew. (I would not place my bets on it.) But barring major external events, there's no evidence to suggest Gen Xers and Millennials are drifting rightward on their own with each passing birthday.

Leaning on a debunked Churchill line for comfort isn't a strategy. It's a recipe for disaster.

Kristen Soltis Anderson is a columnist for the Washington Examiner and author of "The Selfie Vote."