There have been three special elections in the Trump era, and although Democrats have yet to flip a seat, they've gained considerable ground in each compared to results in the general.
Chart: Andrew Witherspoon / Axios
Why it matters: These are tangible signs of progress for Democrats and indicators that the House could be in play in 2018. Princeton electoral politics statistician Sam Wang, citing a 12-point GOP underperformance in the Kansas race and a 7-point underperformance in Georgia, emails Axios that "even a 5-point underperformance in November 2018 would be enough to put House control within reach for Democrats."
We've seen this before: A similar situation unfolded in 2009 when three blue-state seats opened up following Obama's win. The GOP gained ground in each of those special elections (without winning), foreshadowing the 2010 midterms when Republicans picked up 63 seats and took control of the House.
Caveats: 'The Resistance' has invested money and energy into these special elections, juicing the turnout for races that would otherwise be more largely ignored. Jon Ossoff, the Democrat in the Georgia race, raised a state-record $8.3 million. Rob Quist pulled in more than $5 million in the Montana campaign, and it couldn't hurt to have run against a candidate who allegedly assaulted a reporter the night before the election.
Coming up: The final round of the Georgia runoff election between Ossoff and Republican Karen Handel will be on June 20. Mick Mulvaney's vacated South Carolina seat will be up for grabs the same day, and a blue-state seat will be contested in California on June 6.