Fewer congressional contests are expected to be competitive this fall, compared with past election cycles, and experts say the extraordinary mid-decade redistricting efforts initiated by President Trump are largely to blame.

Fewer competitive seats means the overwhelming majority — more than 90% — of congressional races will pretty much be decided during primary elections, which see far fewer voters participate than general elections.

"Right now, we only rate 18 out of 435 races as toss ups, which means that less than 5% of Americans will truly be deciding who's in control of the House," David Wasserman, senior elections analyst for the Cook Political Report, told NPR.

This disparity in the voting power of Americans in congressional races has been a worsening problem for several election cycles.