Washington (CNN) The young blood in the Democratic Party is (still) waiting for its moment.

Democratic leaders across both the legislative and executive branches are generally older than leadership on the other side of the aisle, leading to some restlessness among the lower ranks who have been patiently awaiting their turn at the top.

The most recent blow to those hoping to climb the ranks? Dianne Feinstein, 84, the oldest senator currently serving in the chamber, just announced a bid for re-election to the seat she's held for two and a half decades.

The presidential field also looks like an uphill climb for young Democrats: apart from a couple of standout young senators, names like Bernie Sanders and Joe Biden still loom large among the potential hopefuls.

Part of the problem for Democrats is one of recruiting. Historic losses over the last decade in statehouses across the country have not helped create a bench of energized new lawmakers. Further Democrats have had difficulty winning new seats in the House since the tea party wave of 2010 and redistricting in the wake of that year's census.

Having a generally older slate of leaders could separate Democrats from one of their core constituencies. Younger voters, however, tend to lean more Democratic than older voters. Hillary Clinton won voters under 30 years old by nearly 20 percentage points, while Donald Trump won voters over 65 years old by 7 points, according to exit polls.

Democrats (and Republicans) in Congress are getting older

Members of both parties in Congress are at their oldest average age in decades, but the average Democrat has about four years on the average Republican on Capitol Hill.

The average Democrat was 61.0 years old at the start of this term, the highest average age for Democrats on the Hill in available data stretching back to 1947, compiled thanks to a great piece by 538 , plus recent numbers from the @unitedstates project , an Internet-driven repository featuring data from the Sunlight Foundation, GovTrack.us and the New York Times.

The average Republican was 57.2 years old. The gap between the two parties has been roughly four years since the 2010 tea party wave. For two decades before that, Democrats tended to be about one year older than Republicans, on average.

The 2020 bench

CNN asked Democrats and Democratic-leaning independents last month which person they think best reflects the core values of the Democratic Party. The results?

Top of the list is former President Barack Obama, who can't run for the White House again because of term limits. The average for the next five people — including Joe Biden, Bernie Sanders and Elizabeth Warren — is 71 years old.

It's important to note that the question was not specifically about presidential politics or who should run in 2020. But it does give a picture of who voters see (and don't see) as the figureheads of the Democratic Party.

Of course, President Donald Trump will be 73 years old on Inauguration Day 2020 and he was the oldest first-term President ever to assume office, when he took the oath in 2017. But the average age of the candidates who ran for the Republican primary field in 2016 is just 60 years old, thanks to fresh faces like Marco Rubio and Scott Walker.

The two young names on the list of people who Democrats say share their values are Sens. Cory Booker and Kamala Harris, who each got a nod from 3% of Democrats. Booker is 48; Harris is 52. Then, for good measure, the list rounds out with 77-year-old Nancy Pelosi and 71-year-old Bill Clinton.

This CNN poll conducted by SSRS was conducted from Sept. 17-20 among 493 Democrats and Democratic-leaning independents. The margin of sampling error is ±5.4 percentage points.

Leadership and the old guard

The top three Democratic leaders in the House are in their late 70s. Minority leader Nancy Pelosi is 77 years old, Democratic whip Steny Hoyer is 78 and assistant minority leader Jim Clyburn is 77 years old. Pelosi has held the top spot among House Democrats since 2003.

The aging among Democratic leaders led to a stunning rebuke from the fifth-highest ranking Democrat in the House, essentially calling on her party's top brass in the chamber to step aside.

"I do think we have this real breadth and depth of talent within our caucus, and I do think it's time to pass a torch to a new generation of leaders," said Linda Sanchez, the vice chair of the House Democratic caucus. "I think we have too many great members here that don't always get the opportunities they should. I would like to see that change."

"There comes a time when you need to pass that torch," she said. "I think it's time."

House Speaker Paul Ryan is only 47 years old and Majority Leader Kevin McCarthy is 52. On the Senate side, Democrat Chuck Schumer is 66 and Republican Mitch McConnell is 75.