Mackenzie Eaglen, defense analyst at the American Enterprise Institute.

After years of Republican Party retreat on the need for a strong defense the tide is shifting again. From senior party leaders like Mitt Romney to prospective presidential candidates like Sen. Marco Rubio to grass roots influencers like radio host Hugh Hewitt, conservative columnist Robert Samuelson and the editors at National Review, a consensus is reemerging.

This isn’t just a GOP cause. Increasingly, calls to rebuild America’s military strength are bipartisan. President Obama’s first term policy chief recently penned a piece with her counterpart in the George W. Bush administration seeking a return to defense budget levels of three years ago.

This is more than just an effort to turn off the automatic budget cuts known as sequestration. Stating a desire to end sequestration is already up there with motherhood and apple pie in Washington circles—particularly after the launch of yet another US military operation in the Middle East. A planet simmering with crises is making the public much more aware that reductions in the military’s capacity and capability have gone too far in recent years.

But while many people inside the Beltway say they want to halt the cuts required by the Budget Control Act (BCA), several factors are conspiring to prevent this momentum from possibly leading to renewed American military strength. Due to both political realities and structural spending trends, simple budget relief will not be enough to reverse negative trends.

Rather, policymakers should begin to think about defense differently. They must stop swinging from one crisis to another, repeating the same up-down spending cycles during times of conflict and perceived peace. As defense spending vacillates, so too does global stability since US military retrenchment lowers the bar for conflict overseas.

Lawmakers should concentrate on the outputs produced by maintaining military strength and provide steady, predictable funding. Otherwise, it is increasingly likely more money spent the wrong way will fall short in remedying the Defense Department’s ills.

The Color of Money

Secretary of Defense Chuck Hagel made it clear in his testimony to Congress last week that the Defense Department does not have enough money to meet the military’s rising needs. The Chairman of the Joint Chiefs of Staff followed suit, stressing that the base budget specifically is too low. Gen. Martin Dempsey responded to Senate Armed Services Committee Ranking Member Jim Inhofe’s question of whether he’s adequately funded: “We do have a problem. …And it’s not a problem that we can solve just with [Overseas Contingency Funding]…. There is a base budget issue here, too, we have to get at.”

Only organic base budget growth can invest in rebuilding. That’s because these days, defense dollars just don’t go as far. OCO bump-ups are helpful to be sure, but they’re more like a quick hit than a long-term fix to any of the Pentagon’s problems.

That is particularly important as policymakers increasingly lean toward increasing the defense budget again. An additional dollar in the war budget is not the same as another dollar for the regular Pentagon budget. Generally speaking, money cannot be spent on modernization with these funds for current operations. For an example, look no further than House Appropriations subcommittee chair Rep. Rodney Frelinghuysen’s recent rejection of Joint Strike Fighters and Apaches in this same account for Harriers and F-15s lost in recent operations through a reprogramming request.

A hollow build up is the last thing the Pentagon needs after the last hollow build up that happened after 9/11. And that came after the previous “modernization holiday” and “peace dividend” of the 1990s. While the defense budget grew 42 percent in real terms over the past decade, the number of active duty personnel grew by just 3 percent. Most of the new money after 2001 went toward consumables relating to Iraq and Afghanistan, not increases in the U.S. military’s cutting-edge capabilities.

It is essential to meet the military’s needs for today through supplemental spending, but it is just as critical to adequately invest in the future through the base defense budget.

Defense Budget’s Double Whammy … Has Doubled

While this defense drawdown has been modest by historical standards in both percentage and dollar terms, it is much steeper in practical effect and reduced output. Essentially, what will ultimately be roughly a 20 percent drawdown from peak defense spending in 2010 will feel like more than twice that overall, based on insightful analysis by the Center for Strategic and International Studies’ Clark Murdock. This is due to the rapid decline in defense purchasing power—roughly 15 percent—due to internal cost growth on people’s pay and benefits, aging inventories, maintenance and excess infrastructure.

This essentially means any reinvestment to restore military capacity and capability has a healthy chunk skimmed off the top for other unbudgeted pay downs in areas like infrastructure and benefits. Some of this occurs because Congress has been a significant culprit in raising the military’s cost to rebuild. Year after year, policymakers reject Pentagon proposals to slow the rate of growth within the defense budget—for example rejecting plans to ask for enrollment fees from select retirees receiving TriCare for Life. Every time Congress says “no” to Pentagon plans that have baked-in savings within the President’s budget requires the services have to go back and siphon off money from other priorities.

Another reason defense dollars are losing their proverbial bang for the buck is the cost of rebuilding the readiness of the active military, which costs more than maintaining it in the first place. Restoring readiness in a hurry — something difficult to do as it is within a fixed pipeline of people, training and education — costs more than the actual dollar amount harvested by canceling training exercises or avoiding facility maintenance.

This past spring, for example, the Marine Corps’ F/A-18D fighter jet maintenance backlog grew after readiness funds were cut. Clearing the backlog at depots winds up costing more when there are greater numbers of airframes and engines to fix and shorter time frames with which to do it with limited staff levels.

America’s Two Defense Budgets, OCO and Base

Turning off sequestration, reversing the BCA and getting additional readiness funds immediately — all steps called for by the National Defense Panel — are all big ifs at this point. Still, the odds of any action are better now than any time since the BCA’s 2011 passage.

But the challenge is identifying the right amount of money and where to spend it for the Pentagon. Policymakers will need to manage their expectations about how quickly any additional funds can begin the rebuilding process for the military. The tendency to view the Pentagon’s money problems, and therefore suggested solutions, through inputs—or dollar amounts alone—ensures that rising budgets will not be enough to restore military primacy.

In the aggregate, the Pentagon’s budget is still substantial. The cost of ratcheted up operations, including those in Iraq and Syria, are small and manageable by comparison. But additional money for combat operations against ISIS or counter-terrorism or forces in Afghanistan is not enough to begin to reverse course.

Reversing sequestration is only half the budget battle. Full repeal of the Budget Control Act’s impact on the Defense Department and beginning base budget increases is required to begin to return the force to an acceptable level of readiness and healthiness and with the proper balance between capacity and capability. Too often, the proposed solutions deal with only a fraction of half of the debt reduction law and focus only on spending levels.

Congress needs to think anew about the national defense. The military’s readiness and ability to respond do not turn on a dime. It takes time, partnership and money to reverse.