Escalating their fight over the Pennsylvania congressional map imposed by the state Supreme Court, Republicans are preparing at least two separate legal challenges in federal court seeking to block the new district boundaries.

Top Republican state lawmakers were continuing to work Tuesday on the challenge they had promised even before the court acted Monday, and Republicans on the national level said they were planning a second lawsuit. The suits could be filed as early as Wednesday.

"The suit will highlight the state Supreme Court's rushed decision that created chaos, confusion, and unnecessary expense in the 2018 election cycle," National Republican Congressional Committee spokesman Matt Gorman said in a statement Tuesday morning. He said state lawmakers also would join in that suit, which could be filed "as soon as tomorrow to prevent the new partisan map from taking effect."

If one of the challenges should succeed, voters and candidates — already confused and scrambling to understand new political boundaries — could be left in limbo weeks before the first ballots are to be cast in the primary election in May. Experts, however, said the challenges would face daunting odds.

News of the second lawsuit came soon after President Trump tweeted encouragement to Republicans, saying he hoped they would fight the map "all the way to the Supreme Court, if necessary."

House Speaker Mike Turzai (R., Allegheny) said the challenge that he and Senate President Pro Tempore Joe Scarnati (R., Jefferson) were preparing would focus on "jurisdiction issues."

"It is virtually unheard of for a state Supreme Court to invalidate federal laws on the basis of the state Constitution," Turzai said in a meeting with the Pittsburgh Post-Gazette's editorial board, repeating an argument that he and Scarnati have made for weeks: The U.S. Constitution delegates map-making responsibilities to state legislatures, meaning the court is overstepping its bounds.

The state high court also drew the map on principles not explicitly laid out in the state constitution, he said, calling it "judicial lawmaking at its worst."

Lawyers for the plaintiffs who brought the case that resulted in the new map urged Republicans to stop fighting.

"Pennsylvania's Republican leaders do not know when to quit. Any attempts by them to run to federal court again to stop the new map are without any legal or factual basis," they said in a statement. The new map, they said, is nonpartisan and has more competitive districts. "We hope they have the sense to admit their map has reached its end and stop holding onto their partisan gerrymander."

Interactive: Compare the new map with the proposed fixes for Pa.’s gerrymandered congressional map

Pennsylvania’s most recent map of congressional districts was declared an unconstitutional partisan gerrymander by the state Supreme Court, sparking a nasty political and legal fight and setting off a scramble to draw a new map for the 2018 midterm elections. Click here to compare the new map, the proposals from the participants, and the 2011 plan.

The fight over the maps has major implications for who wins control of Congress in November. Democrats need to add 24 seats across the country to gain a majority in their often acrimonious relations with President Trump, and the new Pennsylvania map is likely to increase their chances of winning several key races in the swing state.

Under the new map, Trump would have won 10 congressional districts in the 2016 election, two fewer than he actually carried under the old map, according to an analysis of election results. (One of the districts won by Clinton would have been essentially a toss-up, with the Democrat winning a slim 50.6 percent of the two-party vote.)

Election analysts are predicting that Democrats could add between three and six seats from Pennsylvania, with some of their best opportunities in the Philadelphia suburbs.

Republican-held seats based in Delaware County and the Lehigh Valley are now leaning toward Democrats as incumbents in both races retire, the Cook Political Report, a political handicapper, said Tuesday. A Chester County seat held by Republican Rep. Ryan Costello is now a toss-up, Cook said, and several other once-strong Republican districts have become potentially competitive in a Democratic wave. Sabato’s Crystal Ball, another election analysis site, agreed.

The new boundaries should stand, according to experts who have said that federal courts are unlikely to intervene in a case decided on state law.

As several pointed out, Scarnati and Turzai have fought the court’s ruling for weeks in an increasingly nasty political and legal battle but have been unsuccessful.

Just days after the state Supreme Court overturned the congressional district map, the top Republican lawmakers asked the U.S. Supreme Court to step in and stay the order, arguing that the state court was usurping the legislature’s power. That request was denied by Justice Samuel A. Alito Jr., who did not refer the matter to the full court, as is often done, noted Michael Li, a redistricting expert at the Brennan Center for Justice at New York University.

“If you’re a Republican defending a map and you can’t even get Justice Alito to refer the thing to the whole court, that’s a pretty weak challenge,” he said Monday, saying he could not think of a challenge that would be successful.

Turzai did not get into detail about the logistics of the impending filing, saying there were several possibilities for where it could be filed and what it could look like. Speaking for himself, Turzai said he believed the suit should request a stay on the new map’s implementation until the U.S. Supreme Court decides other partisan gerrymandering cases this term.

Asked why federal courts would step in when Alito had already declined the earlier request, Turzai said “it’s now riper” because “a map is in front of them. And you get the additional factor that it’s a partisan map.”

“It is clear that this was drawn with the intent of reducing Republican representation in Congress,” he said.

Republicans also received support Tuesday morning from the president.

“Hope Republicans in the Great State of Pennsylvania challenge the new `pushed’ Congressional Map, all the way to the Supreme Court, if necessary,” he tweeted. “Your Original was correct! Don’t let the Dems take elections away from you so that they can raise taxes & waste money!”

James A. Gardner, a University of Buffalo law professor and expert in elections law and state constitutions, said the Pennsylvania Supreme Court had not overstepped its bounds.

“As far as the law is concerned, this is entirely a matter of state law, there is no legitimate ground for trying to run up to the [U.S.] Supreme Court,” he said. “A constitutional crisis? No. This is perfectly normal procedure. This is how it works.”

Time is also running out. To keep the May 15 primary election date, the Pennsylvania Department of State already has delayed the nomination petition period for candidates; petitions are set to begin circulating next week.

“I would bet that this is the map that Pennsylvania uses for the 2018 elections,” Li said.

Staff writer Jonathan Tamari and Pittsburgh Post-Gazette reporter Chris Potter contributed to this article.