Former Speaker Newt Gingrich is downgrading his forecast for a Republican House takeover.

Given the special-election victory by Democrats in Pennsylvania this week, Gingrich said, his party has a 50-50 chance of winning back the House in November.

“I would’ve said more [than 50-50] if they picked up Pennsylvania,” Gingrich told The Hill on Thursday. “I would’ve said they’d gain 70 seats. Now they’re in the 30-to-50-seat range.”

House Republicans need to pick up 39 seats to win a majority.

Rep. Mark Critz (D) defeated Republican Tim Burns by a larger-than-expected margin of eight percentage points on Tuesday to win the seat left vacant by Rep. John Murtha’s (D) death. Critz was sworn in to office on Thursday.

Gingrich, the GOP whip when Republicans won the House in 1994, said Republicans must win close elections to take over the House.

“Forcing your way over the top in tough races matters,” Gingrich said. “I’m a little concerned we didn’t force our way over the top.”

Gingrich said Critz won voters by running to the right of most Democrats. He also benefited from Democratic turnout due to the hotly contested Senate Democratic primary between incumbent Arlen Specter and Rep. Joe Sestak, which Sestak won.

Republicans had believed they had a strong shot at winning the seat. Though registered Democrats outnumber Republicans in the district, its voters tend to be socially conservative and had backed Sen. John McCainJohn Sidney McCainSenate's defense authorization would set cyber doctrine Senate Dems hold floor talk-a-thon against latest ObamaCare repeal bill Overnight Defense: Senate passes 0B defense bill | 3,000 US troops heading to Afghanistan | Two more Navy officials fired over ship collisions MORE (R-Ariz.) in the 2008 presidential election.

Incumbents from both parties face a “very tough” environment, Gingrich said. He noted the victory of Rand Paul in a Kentucky GOP Senate primary over a candidate backed by Senate Minority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellSenate passes 0B defense bill Overnight Health Care: New GOP ObamaCare repeal bill gains momentum Overnight Finance: CBO to release limited analysis of ObamaCare repeal bill | DOJ investigates Equifax stock sales | House weighs tougher rules for banks dealing with North Korea MORE (Ky.) and the loss by Sen. Bob Bennett (R-Utah) to two candidates who criticized him for being insufficiently conservative.

Gingrich said the themes of this year’s election will be to “replace the establishment” and “change Washington’s tone.”

“Bob Bennett’s a good man, a very conservative, solid guy, [but] people wanted an aggressive tone of change,” Gingrich said. “Rand PaulRandal (Rand) Howard PaulSenate Dems hold floor talk-a-thon against latest ObamaCare repeal bill Overnight Defense: Senate passes 0B defense bill | 3,000 US troops heading to Afghanistan | Two more Navy officials fired over ship collisions Lawmakers grapple with warrantless wiretapping program MORE defeated the entire establishment on an aggressive tone of change. The Democrat in Western Pennsylvania won by saying he was pro-gun, pro-life, against ObamaCare.”

Voters want a major change in how Washington spends money, with the federal debt at a record $13 trillion and expected to grow by nearly $1 trillion annually for the next 10 years under President Barack ObamaBarack Hussein ObamaGOP rep: North Korea wants Iran-type nuclear deal Dems fear lasting damage from Clinton-Sanders fight Iran's president warns US will pay 'high cost' if Trump ditches nuclear deal MORE’s policies, Gingrich said.

Gingrich was in the Capitol on Thursday to lend support to the Balanced Budget Amendment Caucus, a group of mostly Republican House members pushing for a constitutional amendment prohibiting deficit spending. The caucus was created this year by its co-chairmen, Reps. Mike Coffman (R-Colo.) and Jim Marshall (D-Ga.).

Gingrich, who has left the door open to a 2012 presidential bid, helped craft balanced budgets with President Bill ClintonBill ClintonGOP rep: North Korea wants Iran-type nuclear deal Lawmakers, pick up the ball on health care and reform Medicaid The art of the small deal MORE in the late 1990s and oversaw House passage of a balanced budget amendment when he was Speaker. The amendment stalled in the Senate.

Gingrich said Thursday that government must make “very significant changes” to its fiscal policy to avoid the kinds of budget crises now seen in Greece, California and New York.

“Government is the fourth bubble, after information technology in 1999, housing in 2007, Wall Street in 2008,” he said. “And government is the biggest of the four bubbles.”

To eliminate deficits now exceeding $1 trillion, Gingrich said, lawmakers could follow the principles used by Republicans in the 1990s: tax cuts to grow the economy, limited spending and the replacement — not reform — of costly government programs such as welfare.

He also called on Republicans to block any tax increase proposed by the bipartisan deficit-reduction commission created by Obama.

“On behalf of conservatism: If they come up with a tax increase, the deficit commission is dead,” Gingrich said.