The Virginia Democrat, who sits on the Senate Armed Services and Foreign Affairs committees, has established a record in the Senate of advocating for restraining the president’s ability to make war without congressional consent.

Clinton, a former Secretary of State, has a national security record marred by her support for the invasion of Iraq, a position she has called a mistake, and for many critics by what seems a reflective tendency to back the use of force. She supported attacks on authoritarians such as Bashar al-Assad in Syria and Muammar Gaddafi in Libya.

Kaine, who is set to speak Wednesday night at the Democratic National Convention in Philadelphia, won’t satisfy anyone who wants the United States’ penchant for military intervention fully reversed. How much influence he’d wield as vice president is uncertain. He is not Clinton’s opposite. He is a cautious politician who keeps his views within striking distance of the mainstream Washington consensus.

But Kaine’s support for military restraint represents a rare area where his views diverge sharply from Clinton’s.

He has established a record as a sort of procedural dove. He has advocated for more congressional power to check the executive branch’s ability to unilaterally wage war. As the Obama administration considered and engaged in military action in Iraq, Afghanistan, Libya, and Syria, Kaine argued that each intervention required approval from Congress.

He has rejected the administration’s claims that an Authorization of Military Force passed in the wake of the September 11, 2001 attacks permits any action by U.S. military forces to combat terrorism.

“I remain deeply concerned about the open-ended nature of the Authorizations for the Use of Military Force in both the wars in Iraq and Afghanistan,” Kaine said in a statement summarizing his efforts on the Senate Foreign Relations Committee.

That stance directly contradicts Clinton’s. She said during her presidential campaign that the 2001 authorization “certainly” permits violence against the Islamic State in Iraq and Syria.

Kaine worked with Republican Sen. Bob Corker of Tennessee on legislation giving Congress a role in approving the administration’s nuclear deal with Iran. He partnered with Sen. John McCain of Arizona in proposing that Congress beef up the 1973 War Powers Act, which requires presidents to consult with Congress on the use of force, a policy White Houses often ignore.

Such positions, usually taken with a Republican co-sponsor, have won the Virginia senator praise from GOP colleagues.

Kaine’s calls for consulting Congress, to be sure, can be a bit of dodge. They leave his view on whether specific military actions should occur a bit murky.

In a 2014 Washington Post op-ed urging the White House to seek congressional approval to act against ISIS, for instance, Kaine did not say if he thought Congress should okay a new authorization.

“I’m open to hearing the case for military action in Iraq, but first we need a new playbook,” Kaine wrote.

Despite such hedging, Kaine’s arguments have a clear upshot. Less war. Presidents enjoy a virtually free hand now to intervene militarily overseas. If they followed Kaine’s call to seek congressional authorization each time, their power would be reduced, making use of force harder and less frequent. Kaine knows that.

“Ultimately, the allocation of war powers is based on a value,” he wrote in the same Washington Post op-ed. “The nation should not send U.S. service members into harm’s way unless there is a consensus among the civilian leadership — executive and legislative — that the mission is worth it. Ordering people to risk their lives without Washington doing the work necessary to reach a political consensus is immoral.”

It is not yet clear if Kaine would curtail Clinton’s hawkishness. There is also no guarantee the senator, who reversed his position on the Trans Pacific Partnership when Clinton selected him as her running mate, would maintain his support for congressional power from the other side of Pennsylvania Avenue. The shift in office certainly helped alter Obama’s view on seeking congressional approval.

Vice President Joe Biden underwent a similar shift. “The president has no constitutional authority to take this country to war,” he argued in 2007, “unless we’re attacked or unless there is proof that we are about to be attacked.” In the White House, Biden dropped that view.

But unlike Obama and Biden in 2007, Kaine is already arguing with a president from his own party on the matter. While he’d presumably be a team player under Clinton, his record on urging congressional authorization would be hard to abandon.

If she wins, decisions of war and peace would be determined ultimately by Clinton, but it’s a good bet Kaine would ben a internal advocate against war.