The US Army's announcement that through 2017 it's cutting end strength by 40,000 more troops made headlines last week, but was hardly a surprise.

For years, service leaders have warned that spending caps would lead to a smaller force. The only question was where those cuts would come from.

End strength stands at about 490,000 troops today, down from 566,000 in 2010. By the end of 2018, troops will have been cut from nearly every US and overseas base, shrinking the active force to 450,000 troops.

And without more funding, service leaders made it clear that further cuts are on the table, making all the more likely a 420,000-soldier Army, as hinted at by the latest Quadrennial Defense Review.

Army leaders have fought hard against troop cuts. Now, forced to act, they're making sure to detail the local economic impacts of the latest round of troop reductions.

Congress has responded with outrage that's not only predictable, but also hypocritical: Legislators can't have a hand in slashing defense spending then complain about the impact of those cuts.

In the interests of national security — should lawmakers get to that after all the grandstanding — Congress must honestly debate America's defense future, from strategy to the required resources.

A good place to start would be to scrap defense spending caps that are both disruptive and encourage budgetary sleight of hand to fund needed priorities.

DoD can and should get more efficient — with a flat budget, it can't afford to keep shrinking to cover the rising costs of modernization, training and people. Each of the services has been trading people for programs and training. While size for its own sake is no virtue, it's equally true that size should be scaled to strategic and projected future missions rather than budget alone.

Today, the military services maintain considerable combat capabilities, but the question is at what point will they become too small to support US peacetime needs in an ever-more complex and fast-moving world, much less to meet major wartime demands.

Given the magnitude of looming modernization programs, there will be a temptation to further shrink the force to cover the costs of key priorities, rather than properly commit more resources to underwrite strategic priorities, such as new bombers and ballistic missile submarines.

Moreover, while President Obama last week went to the Pentagon to make it clear that he wants minimal numbers of US troops directly engaged in fighting ISIS in Syria and Iraq, DoD's new National Military Strategy made it clear that America must prepare for prolonged campaigns against adversarial states and violent extremist organizations.

Sustained operations, even peacetime deployments, naturally put stress on the force, which is why sufficient size during an era of complex and sustained threats is vital.

Some lawmakers, decrying a lack of real strategy, want to craft their own approaches to addressing ISIS and other threats. Congress has a long and successful history of shaping thoughtful and lasting strategies initially opposed by DoD, among them the landmark Goldwater-Nichols legislation that promoted the very jointness that today is key to US war fighting. But those successes came at a time when members and their staffers had deep and broad national security expertise and an ability to set partisanship aside to achieve strategic aims.

It's good news if Congress is serious about more broadly debating strategy. It's even better news if members take the time to educate themselves on national security, craft a strategy that puts national interests ahead of party interests and then fully commits necessary resources.