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Pennsylvania Republicans were handed a pair of defeats Monday in their quest to keep old congressional maps in place for the 2018 midterms, potentially giving Democrats a boost when it comes to winning back the House in November.

The U.S. Supreme Court declined a request from Republican leaders to put the new congressional district map, imposed last month by the Pennsylvania Supreme Court, on hold. Earlier Monday, in a separate case, a panel of federal judges dismissed a legal challenge by Republican congressmen to the new map.

The panel's decision, paired with the Supreme Court declining to block the new maps, makes it likely that this year's congressional elections in Pennsylvania will be conducted under district lines widely viewed as more favorable to Democrats than a 2011 map the state court threw out in January.

The earlier map has been a campaign winner for Republicans, leading them to a 13-5 edge in the state's congressional delegation for all three elections in which it was used.

Before the new map, Democrats in Pennsylvania were looking to pick up two to three seats on a good night. With the new maps, Democrats have a shot at five to six seats.

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And with Democrats needing to pick up 23 seats to win back the House, those extra districts are a big deal.

The three-judge panel issued its decision with just one day left for the state's congressional candidates to circulate petitions to get on the May 15 primary ballot. It said it had no authority to act in the matter except to dismiss the case.

"The plaintiffs invite us to opine on the appropriate balance of power between the Commonwealth's legislature and judiciary in redistricting matters, and then to pass judgment on the propriety of the Pennsylvania Supreme Court's actions under the United States Constitution," the judges wrote. "These are things that, on the present record, we cannot do."

Democratic Gov. Tom Wolf called the ruling the right decision and said it will let the state move ahead with a fair map.

The Democratic majority on the state Supreme Court had ruled in January that a map Republicans crafted in 2011 amounted to an unconstitutional gerrymander.

After Wolf and lawmakers in the GOP-controlled General Assembly did not produce a replacement, the court enacted its own map last month and gave candidates extra time for petition gathering.

Monday's decision comes in a federal case brought a month ago by eight sitting Republican congressmen and two GOP state senators. They argued the state justices infringed on the Legislature's prerogative and did not give lawmakers enough time to come up with a replacement.

The panel said the senators have only two votes in their chamber, calling that "inadequate as a matter of law to allow a lawsuit premised on an institutional injury to the General Assembly." The eight Republican congressmen, the judges wrote, may have wasted resources campaigning in their old districts, but they cannot prove that was caused by a violation of the U.S. Constitution's Elections Clause.

"The cost of shifting district boundaries — in terms of both campaign funding and constituent fealty — is surely appreciable," the judges wrote. "But the federal congressional plaintiffs have identified no legal principle tethering that cost to a legally cognizable interest in the composition of their electoral districts under the Elections Clause."

A group of 18 Democratic voters sued in state court last year to challenge the 2011 map, a case the state Supreme Court put on a fast track before throwing out the former district lines.

All five Democrats on the state Supreme Court said the map violated the state constitution, but one of the Democrats joined both Republicans in objecting to the majority's determination to enact a new map for this year's races.

More than two dozen candidates had filed petition paperwork by mid-day Monday, according to state elections bureau data. The deadline to submit at least 1,000 voter signatures to get on the primary ballot is Tuesday.