They say Republicans are paying a price for blocking Obama's Supreme Court pick.
McGinty will take on vulnerable Sen. Pat Toomey (R-Pa.) in November.
The win puts Van Hollen in a firm position to replace Sen. Barbara Mikulski.
Carlos Beruff is running in the Republican Senate primary in Florida.
Tea Party Express called Stutzman the best choice for the grassroots.
Jon Keyser fell 86 signatures short of the required number to qualify for the GOP primary.
The former Maryland governor praised Van Hollen as "a progressive who will get things done."
Timothy Cama 04/25/16 12:29 PM EDT
NextGen is aiming to get out the vote at more than 200 colleges in seven battleground states.
Rep. Mike Pompeo says he will not challenge Sen. Jerry Moran in a GOP primary.
Donna Edwards said she is "dumbfounded" by fellow Democrats who don't value diversity.