During a retreat in Philadelphia, Republican lawmakers discussed national security, defense and foreign policy. Contributors included Sens. Bob Corker (Tenn.), John McCain (Ariz.), Reps. Ed Royce (Calif.) and Mac Thornberry (Texas). (Obtained by The Washington Post)

On Friday, President Trump announced his plans to lavish spending on the nation’s military in remarks at the Pentagon near Washington. But just one day beforehand, congressional Republicans debated the costs of such a buildup and how to pay for it at their annual policy retreat in Philadelphia.

Senate Foreign Relations Committee Chair Bob Corker was the most outspoken in questioning whether Republicans would be able to stomach making the kind of cuts necessary to fund a Republican wish list of new defense and foreign policy priorities.

“I’m sorry, I wonder sometimes where we as a party are going,” Corker (R-Tenn.) told a roomful of House and Senate Republicans Thursday during a national security discussion, adding that he was “discouraged” by the apparent lip service being paid to the potential costs.

“There’s a spending side of this that if we don’t deal with, we’re not going to come close to defending the needs of our country,” he warned. “I fear that we’re going to leave here without thinking of the other side of the equation.”

Corker’s remarks were part of a recording of several private sessions held this week at the GOP retreat in Philadelphia and later sent to The Washington Post and several other news outlets from an anonymous email address. The identities of the lawmakers in the recordings were verified by Post reporters.

Spokespeople for Corker, Senate Majority Whip John Cornyn (R-Texas), Sen. John McCain (R-Ariz.) and House Armed Services Chair Mac Thornberry (Texas) — all of whom are heard in the recording — either did not return requests to comment or declined to comment for this story.

Republicans also fretted about the consequences of quickly repealing Obamacare, according to a recording of another closed session at the retreat; and Vice President Pence vowed that the administration would undertake an extensive examination of the voter rolls after Trump’s claim that 3 million to 5 million people voted illegally in the November election.

The conversation about defense spending among Hill Republicans reveals a potentially troublesome rift for the party between those who want to strengthen the military with more spending and the traditional stance of many Republicans that new spending needs to be paid for elsewhere in the budget. Trump made clear where he stands this week when he told Fox News’s Sean Hannity that he wasn’t worried about increasing the deficit by strengthening the military.

“Our military is more important to me than a balanced budget,” President Trump told Hannity on Thursday.

In an executive order signed at the Pentagon on Friday, Trump signaled his intention to embark on a “great rebuilding of the Armed Forces,” ordering a review of the military’s war-readiness and the country’s nuclear and ballistic missile defenses.

In order to pay for more defense spending, however, the GOP would first have to lift budget caps that were part of the 2011 Budget Control Act, or move new funding into a separate account for emergency war funding that isn’t counted against the caps known as sequestration. Trump called for an end to the defense sequester on the campaign trail.

Corker began Thursday’s session by challenging his colleagues to “prioritize within our own government” in order for the country to be successful on the world stage without going broke. But by the end of it, he questioned whether Republicans were willing to pay for a burgeoning military with major financial reforms to entitlement programs like Medicaid, Medicare and Social Security. Trump has said he does not intend to dip into those popular programs to fund his agenda.

“Unless we have the moral fortitude and courage to deal with the elephant in the room, all this other stuff we’re talking about is a total waste of time,” Corker said. “National security is our first responsibility, but leaving the nation greater for other people certainly is up there, and we’re not willing to deal with this?”

Cornyn also appeared concerned about how to pay for a substantial military buildup without big cuts elsewhere, suggesting lifting the budget caps was insufficient.

Cornyn warned against trying “to deal with this by just tinkering around with sequestration. We’re not going to just deal with this by tinkering around with overseas contingency spending,” he said, referring to the emergency war funding measures lawmakers have relied on to cover some budgeting shortfalls over the last few years.

“Unless we deal with the 70 percent of spending that’s mandatory spending … then we’re never going to pick up enough money to be able to appropriate for what our national priorities are, starting with the military,” Cornyn added.

GOP hawks in Congress have argued for years that the country needs to at least replenish defense spending lost because of across-the-board budget cuts. They point out that the cuts have cost the military in terms of the health and viability of its aircraft and ships, and the readiness of its members — particularly pilots, some of whom have been reduced to as little as four hours of training flights per month.

“I say to the defense doves … we need to negate the effects of the Budget Control Act,” McCain said, according to the recording, calling the current way of funding the Pentagon “a disgrace.”

“While we’re dealing with our fiscal problems, there are men and women risking their lives to protect us and we have got to support them along the way,”said House Armed Services Committee Chair Mac Thornberry (R-Texas).

Some of the Republicans bemoaned the idea that the military’s capacity shrunk during the course of former President Obama’s tenure. They listed the threats to the United States as emanating chiefly from Russia, China, Iran, North Korea, and extremist groups such as the Islamic State, pointing to everything from nuclear strikes to cyber attacks. Cyber, McCain warned his colleagues, “is the one aspect of our potential confrontation where I believe that our adversaries are ahead of us.”

The Republican leaders expressed a great degree of confidence in Trump’s Cabinet appointees to steer defense and foreign policy, particularly retired Gen. James Mattis, who was recently confirmed as secretary of defense; Rex Tillerson, who is likely to be confirmed by the Senate next week as secretary of state; and even Gen. Mike Flynn, Trump’s pick to serve as national security adviser.

But not all of them are completely sold on Trump himself just yet.

“We have to have a little straight talk here. I don’t know what the president’s policy towards Russia is,” McCain told his colleagues, stressing that Trump had to be tough on the Kremlin and Russian President Vladimir Putin.

“He is bent on restoring the Russian empire,” McCain said of Putin. “He is a thug and a bully and we can’t treat him any other way.”

Mike DeBonis contributed to this report.