In “Talk to Tehran, but Talk Tough” (Op-Ed, Jan. 19), Nicholas Burns, a former under secretary of state, calls for President Obama and whoever succeeds him to find a “right balance” on Iran that straddles “between cooperation on nuclear issues and containment of Iranian aggression.” The surefire way to ensure that Iran abandons its obligations under the deal is to return to a policy of coercion.

Mr. Burns is right that Iran’s political system is not monolithic. There are forces that were critical of the nuclear negotiations, arguing that Iran gave up too much and that the United States cannot be trusted to follow through on its commitments. For more than 200 years, Iran’s sovereignty, independence and integrity have come under threat from world powers and regional conflicts. This has made Iranians resistant to occupation or submission.

An American approach centered on engagement, compromise and negotiations carried out with respect is what made the nuclear deal possible — not a policy based on coercion, which over years of use bore nothing but an expanded Iranian nuclear program. Iran responds positively to the language of respect, but becomes aggressive and inflexible when faced with threatening language or pressure.

“If the Americans show, in words and actions, that they are not irrational, then they will see that the Islamic Republic and the people of Iran are well-wishing, reasonable and cooperative,” Iran’s Leader, Ayatollah Seyyed Ali Khamenei, has declared.

Engagement with Iran has a username, which is “diplomacy,” and a password, which is “respect.” Adopting this approach is the key to managing regional crises, whether in Syria, Yemen or elsewhere.

• Seyed Hossein Mousavian, a former Iranian diplomat, is a research scholar at the Woodrow Wilson School of Public and International Affairs at Princeton.

 A version of this letter appeared in print on January 27, 2016, on page A26 of the New York edition of the New York Times.