Is it possible to cut through the noise of two nights of Democratic presidential debates and get a real sense of whether these contenders are ready to take us past the broken politics that put Donald Trump in office?

Absolutely. A pair of simple “yes” or “no” questions—suggested by a piece of legislation advanced this week by Congressman Ro Khanna (D-CA)—will do the job.

But first some context: Since World War II, presidents have taken us to war without the congressional declarations that the Constitution requires. And Congress has let them get away from it. Trump loves this precedent. He’s even said that while he likes keeping members of Congress “abreast” of his erratic deliberations about ordering attacks on other countries, “I don’t have to do it legally.”

Yes, there’s a Constitution that says different. Yes, House Speaker Nancy Pelosi (D-CA) says the president needs congressional approval before he embarks on “hostilities” against Iran. Yet, Trump told The Hill this week, “I disagree. Most people seem to disagree.”

This president needs to be told that he is wrong—not in some abstract or theoretical sense but in the clear and unequivocal manner that sets a standard for Trump and the presidents to come. He needs to be reminded that, as Khanna says, “Congress decides when we go to war. That is a fundamental aspect of our system of checks and balances, and we intend to hold our president to his constitutional responsibility.”

By “we” he means House Foreign Affairs Committee chair Eliot Engel (D-NY), House Armed Services chair Adam Smith (D-WA), House Rules Committee chair Jim McGovern (D-MA), Congresswoman Barbara Lee (D-CA), and the other original co-sponsors of a bipartisan amendment to the annual National Defense Authorization Act (NDAA) that Khanna has written—with Republican Congressman Matt Gaetz of Florida—to prevent the use of federal funds for any military action against Iran that lacks congressional authorization. (Khanna is a backer of Vermont Senator Bernie Sanders, but one of the cosponsors of the amendment is another Democratic presidential contender, Massachusetts Congressman Seth Moulton.)

The amendment is specific. It clarifies that Trump cannot use the 2001 and 2002 Authorizations for the Use of Military Force, which have so frequently been abused by presidents to “justify” unauthorized military actions, as an excuse for attacking Iran.

Presidents have a responsibility to defend the United States. But that responsibility cannot become a rationalization for launching undeclared wars. Even after the December 7, 1941, attack on Pearl Harbor, President Franklin Roosevelt obtained declarations of war from the full House and Senate. “This bipartisan amendment is a vital safeguard against unilateral actions by this president who selected the architect of the Iraq war to be his national security advisor,” says Khanna. “This amendment is also proof that opposition to war with Iran transcends partisan politics. With this effort, Americans can come together around the idea that we must stop a war with Iran.”

This unified message is necessary because, as the congressman notes, “President Trump campaigned on ending costly wars overseas but given the advisors he chose and his recent risky actions, he is not living up to that promise.”

Which brings us back to the questions that should be asked of the Democratic candidates at the debates on Wednesday and Thursday nights.

Here’s the first question: Yes, or no, do you support the bipartisan amendment sponsored by Congressman Ro Khanna and key House members to bar the use of federal funds for any exercise of military force against Iran that lacks explicit congressional authorization?

Here’s the second question: Yes, or no, would you as president accept the standard outlined in the Constitution, and reasserted by the Khanna-Gaetz amendment, that presidents must obtain formal approval from both houses of Congress before using military force?

The candidates will, of course, want to say more. That’s fine.

But if we can start with a “yes” and a “yes” from each of them, that’s significant. And if any of the candidates answer “no” to either question, or if any of them equivocate in any way, well, that’s even more significant.