As you slept Monday night, Democratic Senators talked and talked (and talked) about climate change.

The theatrics have very little to do with the chances of passing climate legislation this year -- the chances of that are roughly zero percent -- but do tell us something about how Democrats are pivoting to make climate change a bigger campaign issue in 2014 and, especially, 2016. The shift is aided in part by major campaign contributions from climate legislation supporters, but also backed up by recent academic research showing pro-green Democrats received an electoral boost in recent elections.

For years, global warming has ranked at the bottom of Americans' to-do list for Congress, trumped by the economy, budget and entitlements and terrorism. A January Pew Research Center poll found just 29 percent saying it's a "top priority" for President Obama and Congress this year, ranking 19th out of 20 issues tested. Protecting the environment ranked higher at 49 percent, but was still 12th from the top.

A Member of Congress could hardly imagine losing their seat on the issue of climate change, even as clear majorities both a)believe humans are causing global warming and b) support regulating greenhouse gases to mitigate its effects.

That conventional wisdom of climate change as a dead weight issue is challenged by a Stanford University study based on the 2010 congressional elections, which found Americans voted, at least in part, on candidates' climate change positions.

In one study, Stanford's Bo MacInnis, Jon Krosnick and Ana Villar compared what candidates said (and didn't say) on climate change in every 2010 congressional and Senate election to how much Democrats won or lost by. In short, they found Democrats who took pro-green stances such as "global warming has been happening" increased their vote margin over Republicans by 3 percent compared with those who didn't. The impact was much larger -- a 9 percent vote-margin swing -- when a Republican took a position doubting global warming's existence or opposing action to address the issue. The analysis controlled for the district or state's partisan lean in the 2008 election, as well as for whether the candidate was an incumbent.

The paper included two other experiments that supported a similar theme that climate change may not be politically as toxic as once thought for Democrats, and could boost their support. But as the Post's Ed O'Keefe notes, only two Democrats facing difficult re-elections are among the expected speakers, an indicator Senators in competitive races may still be leery to invite attacks from climate regulation opponents.

Whichever candidates take up the climate legislation mantle, the 2014 election will be a key test of its influence.

Juliet Eilperin, Ed O'Keefe and Peyton M. Craighill contributed to this report.