The Top Threat to the United States? Take Your Pick.

What’s the top threat to America? It depends on which high-level Pentagon official you ask.

In a series of hearings on Capitol Hill this week, there was some agreement among Defense Secretary Ashton Carter, Joint Chiefs Chairman Gen. Martin Dempsey, and Gen. John Campbell, the top U.S. commander in Afghanistan. But hours of questioning by House and Senate lawmakers revealed subtle differences in opinion, offering a glimpse at the broad range of threats Pentagon planners are simultaneously confronting.

Both Carter and Campbell believe the fragile security situation in Afghanistan and the potential reach of the Islamic State into the war-torn country are top priorities. On Wednesday, Carter urged lawmakers not to place time limits on the fight to defeat the group to ensure its defeat.

“I wouldn’t assure anyone that this will be over [in] three years or that the campaign will be completed in three years,” Carter said.

Campbell, speaking to the House Armed Services Committee Wednesday, added that concerns about the group’s emergence in Afghanistan are growing, and left the door open to changing plans to withdraw the majority of U.S. troops by the end of 2015.

Dempsey had a slightly different take. He told lawmakers Tuesday that the threat from radical Islamist groups proliferating around the world — as opposed to a specific region — is alarming.

“We are also seeing power in the international system shifting below and beyond the nation-state, particularly across the network of radical movements that use terrorism as a tactic,” Dempsey said.

One concern both Carter and Dempsey agreed was a priority was Russia. On Tuesday, Dempsey joined Carter’s long-standing request for the White House to consider sending lethal assistance to Ukraine to help fight Russian separatists. Their call to arms came as U.S. and European lawmakers consider new sanctions against Russia and its increasingly belligerent President Vladimir Putin.

“I think we should absolutely consider lethal aid and it ought to be in the context of NATO allies because Putin’s ultimate objective is to fracture NATO,” Dempsey said.

They also concurred that sequestration — the budget cuts mandated by the Budget Control Act of 2011 — posed a grave threat to national security. President Barack Obama has asked Congress to approve a $534 billion base defense budget, along with $51 billion in overseas contingency funds. Together, that busts budget caps set by the 2011 legislation by $35 billion.

Their pleas for more spending flexibility fell on deaf ears, however, as Republicans and Democrats on the committee made clear Wednesday that they would draft a spending bill that sticks to sequestration requirements.

Photo Credit: Chip Somodevilla