A Pennsylvania court ruled today that Rep. Jason Altmire had enough valid signatures to stay on the Democratic primary ballot with fellow Rep. Mark Critz.

Critz will likely appeal the decision to the state Supreme Court. After the ruling, Critz campaign adviser Mike Mikus said they disagree with the judge’s decision and “are currently exploring our legal options.”

Several weeks ago, Critz challenged Altmire’s ballot access after he turned in only 1,651 nominating signatures. Pennsylvania election law requires 1,000 signatures to get on the ballot for Congress, but campaigns typically file twice as many to ward off these kinds of challenges.

Critz’s case came down to the residency of a junior Altmire staffer, Abby Silverman, who collected almost 300 signatures. Pennsylvania law states Silverman must live in the 12th district to collect signatures for Altmire. Silverman is registered to vote at her parents’ house inside the district, but she lives in an apartment in a nearby district.

“In filing this unsuccessful challenge, Mark Critz has lowered himself to tactics usually reserved for elections to high school prom king, rather than the United States Congress,” Altmire said in a statement following the ruling.

Until the ballot challenge, Pennsylvania insiders favored Altmire to win the primary. Critz’s own poll in February showed him trailing Altmire by 10 points, and Altmire currently represents more of the redrawn district.

Republicans redrew the Congressional map in Pennsylvania late last year. The state lost a seat following reapportionment, so mapmakers moved Critz and Altmire into the same southwestern seat.

Republicans will likely nominate attorney Keith Rothfus next month. Rothfus barely lost to Altmire in 2010 in the current 4th district.