Republican appropriators said they’re forced to make such heavy cuts in discretionary spending because the White House and Congress haven’t made a deal to sufficiently reduce mandatory spending, such as entitlements.

The Interior-EPA bill is the first fiscal year 2014 spending plan “where push comes to shove in this budget cycle,” House Appropriations Committee Chairman Hal Rogers (R-Ky.) said Tuesday.

The deeper cuts for Interior and the EPA stem, at least in part, from appropriators’ decision to approve higher spending for programs like defense in earlier bills. But the bill also allows Republicans to go after one of their favorite political targets: the EPA.

Republicans included a slew of riders that would block EPA actions, including the agency’s proposals to control greenhouse gas emissions from power plants — a central part of Obama’s plans to address climate change. The bill would also block the EPA from moving ahead with its proposed Tier 3 rule on sulfur in gasoline or finishing its rule for cooling towers on power plants and major manufacturing facilities.

“There is a great deal of concern over the number of regulatory actions being pursued by agencies in the absence of legislation and without clear congressional direction,” subcommittee Chairman Mike Simpson (R-Idaho) said. “This is especially true with the EPA.”

But top subcommittee Democrat Jim Moran of Virginia stormed out of the markup, calling the bill a “disgrace.”

“It should be an embarrassment to the subcommittee, the full committee and to the Congress as a whole,” Moran said.

He noted that the cuts come less than a week after the Senate confirmed Gina McCarthy to head the EPA after a record-long nomination fight.

“In fact, even her own office is cut by 20 percent,” Moran said, adding: “We know that if we had a job to do and somebody cut our resources by 20 percent, it would be very, very difficult to fulfill the missions that Congress has given.”

Moran estimated that Tuesday’s bill contains 31 “special interest earmarks,” including 13 “brand-new” riders that Republicans didn’t warn him about ahead of time. Nine riders protect the grazing industry; six “limit the EPA from being able to provide clean water”; and four “prevent EPA from implementing clean air regulations,” he said.

Moran said he had expected the usual riders aimed at blocking the Interior Department from funding its “wild lands” program and trumping enforcement of the EPA’s lead paint rule. But he was not expecting GOP members to blindside him with the new riders, which also include language prohibiting the EPA from changing its regulations on the pesticide sulfuryl fluoride.

“I just can’t participate in this markup,” Moran said before walking out.

Simpson said, “I’ll mark you down as undecided.”

Appropriations ranking member Nita Lowey (D-N.Y.) noted that the GOP plan would give the EPA the same funding levels it saw during the Reagan administration and said clean water and safe drinking water revolving loan funds would be cut by 83 percent and 61 percent, respectively. “Unfortunately, this bill’s disastrous levels and atrocious riders exemplify that the road to redemption is long for this committee,” Lowey said.

Moran’s protest was mere theater, and, as usual, the real debate on the spending bill won’t happen until the full committee takes it up — with Tuesday’s markup continuing the tradition of not offering amendments until the full panel.

It also underscored the reality that political messaging is the main point of House spending bills that stand little to no chance of getting through the Senate and becoming law.

On the other hand, the bill signals the potential elements of a compromise down the road if lawmakers are able to fashion a bicameral deal on Interior-EPA spending and the larger deficit.

Both Simpson and Rogers acknowledged as much, saying the Interior-EPA draft was intended to prove a point — that Obama and Republicans have to agree on cutting mandatory spending.

“I fully expect to take a lot of heat over some of these decisions,” Simpson said. “But my intent is to show what happens when Congress allows mandatory spending to grow and grow and places the burden of cutting spending solely on the discretionary side. It’s an unsustainable pattern that must be addressed and very soon.”