In yet another sign of a huge leftward swing in American politics, a Democrat won a seat in the New York State Assembly Tuesday night that has been held by Republicans for 40 years.

Democrat Steve Stern defeated the Republican Janet Smitelli in the Westchester-area seat with an 18-point margin, 59 percent to 41 percent.

Vox's Matt Ygelsias wrote that the win serves "as a further sign of the strong wind at Democrats’ backs downballot in the Trump era, with their candidate Steve Stern running 11 points ahead of Hillary Clinton’s 2016 margin in the seat and 15 points ahead of Barack Obama’s 2012 margin."

Many have argued that the wide margins with which Democrats have been winning in special elections suggest that a "blue wave" could be coming for the 2018 midterm elections, with Republicans poised to lose dozens of seats in the House of Representatives and possibly even control of the Senate.

The New York State Assembly is already controlled by Democrats, so the change may not make a huge difference when it comes to state politics. But Democrats across the country can feel more confident about their party's chances in 2018 as they celebrate their 40th flipped seat of the President Donald Trump's first term.