Democrats favor impeaching Trump. So why did Democratic lawmakers oppose it?

Exhibit A: Democratic Rep. Al Green of Texas forced a vote on the House floor to table a plan to impeach Trump on Wednesday. The vote to sideline the impeachment resolution passed with flying colors: a bipartisan 364-58 margin.

And while nearly five dozen Democratic members of Congress took to the chamber's floor to cast their votes in favor of mulling impeaching Trump, more than twice as many Democrats opted to cast their ballots against the proposal.

A new poll from the Public Religion Research Institute on Tuesday found that seven in 10 Democrats believe Trump ought to be impeached and removed from office. Still, only about three in 10 of House Democrats actually voted to consider impeachment on Wednesday.

So why the disconnect between Democrats and Democratic lawmakers? One hint might be found in Wednesday's roll call vote.

The 2016 election results can give a little more insight into the division in the Democratic caucus and why the idea of impeachment just hasn't caught on yet.

Hillary Clinton's margin of victory was almost 20 percentage points wider in districts with representatives who cast ballots to consider impeachment on Wednesday vs. those who voted to table the proposal.

In fact, 15 of the two dozen Democrats in the safest Democratic districts, based on the Cook Political Report's partisan voter index, voted to consider articles of impeachment vs. only two Democrats in the 54 most vulnerable districts who did the same. (One of those in the safest districts who voted to sideline the impeachment proposal? House Minority Leader Nancy Pelosi.)

A joint statement from the top two ranking Democrats in the House, California's Pelosi and Maryland Rep. Steny Hoyer, made clear why Democratic lawmakers weren't on board with pushing for impeachment.

"Now is not the time to consider articles of impeachment," they wrote in a press release on Wednesday, while still asserting that "legitimate questions have been raised about his fitness to lead this nation."

"Right now, Congressional committees continue to be deeply engaged in investigations into the President's actions both before and after his inauguration. The special counsel's investigation is moving forward as well, and those inquiries should be allowed to continue."

Here's another helpful metric for understanding this: the partisan voter index, a number given by The Cook Political Report to every US House district in the country based on how Republican or Democrat it leans.

The average PVI in districts where House members voted to consider impeachment was Democrats +22 vs. Democrats +13 in districts with House members who voted to sideline the plan. That means Democrats in safer districts --- in areas that leaned overwhelmingly blue --- were more likely to entertain the idea of impeachment at this point.

It's not a particularly novel idea that Democrats in potentially more vulnerable seats are less likely to get on board with an idea that, at least in this moment, is still not even near politically ripe for the party bosses. And it's clear national Democrats see there's danger in pushing the issue right now. Opponents of the president have their work cut out for them if impeachment is the ultimate end game.