(CNN) The political world's focus on the possible impeachment of President Donald Trump by the House has obscured a critical shift in the battle for control of the Senate: Democrats now have a genuine chance at retaking the majority come November 2020.

"With President Donald Trump struggling to recreate his 2016 Electoral College victory, control of the Senate should be regarded as in play," Nathan Gonzales, a non-partisan political handicapper and publisher of "Inside Elections ," said in his tipsheet. "Republicans are still more likely than not to maintain control of the Senate, but Democrats have a legitimate path to control, particularly if they win the White House."

This is a big deal -- for a number of reasons, not the least of which is that the Senate is tasked with confirming (or not) presidential picks for the Supreme Court. Trump was able to get two conservative justices through the Senate -- Neil Gorsuch and Brett Kavanaugh-- during his first term and, due to the advanced age of a number of the justices, there exists a very real possibility of several more openings on the nation's highest court within the next few years.

Beyond that, a unified Democratic Congress -- assuming Democrats keep control of the House -- could be a massive boon for a newly elected Democratic president in 2021 or a major thorn in the side of Trump as he seeks to build a legislative legacy in his second term.

So why are Democrats now in a better position to make that scenario a reality? A combination of a continued decline in the national political environment for Trump coupled with strong fundraising numbers by a slew of Democratic challengers.

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