In the days following President Trump’s appointment of Ambassador John Bolton as national security advisor, his critics have been out in full force. But they have painted a caricature of him that is inaccurate and unfair. Bolton is an accomplished lawyer, diplomat and thought leader, having spent many years in public service. In 2001, he was named US undersecretary of state for arms control and international security, and from 2005 to 2006, he served as the US permanent representative to the United Nations (UN). One of us (Sen. Lieberman) joined a small group of Senate Democrats to support Bolton’s confirmation as an undersecretary of state, and the other (Ambassador Wallace) served under him at the UN. In our judgement, Ambassador Bolton has a breadth and depth of experience in national security, and a reputation for knowing the ins and outs of Washington. These qualities will make him an effective national security advisor. The John Bolton we know has an unmatched intellect, dry sense of humor, strong moral compass and can be counted on to be a principled champion for American leadership. Contrary to his reputation as a proponent of "America alone," as an undersecretary of state, he spearheaded the groundbreaking Proliferation Security Initiative, which eventually enlisted more than 100 countries to thwart the trafficking of weapons of mass destruction and their delivery systems to and from state and non-state actors of proliferation concern. Ambassador Bolton also nurtured efforts to reform the UN — to this day one of the most bloated bureaucracies in the world. After his tenure, Ambassador Bolton joined us at United Against Nuclear Iran (UANI), a bi-partisan advocacy group, to highlight the danger the Iranian regime poses to the international community. Alongside UANI, Ambassador Bolton worked with experts from both sides of the aisle, fostering dialogue and debate, and proposing actionable ideas to combat the threat posed by Iran. He has spoken with consistency and clarity on the flaws of the Joint Comprehensive Plan of Action (JCPOA) and the potential for a US withdrawal. We are confident that as national security advisor, Ambassador Bolton will continue his commitment to standing up to rogue regimes and nefarious non-state actors. Ultimately, Ambassador Bolton sees his new role as an honest broker. He understands that the major responsibility of his new job is to present the president with policy options on important national security challenges, and to make recommendations when the commander-in-chief asks for them. This will be ever more important as the nation faces a host of challenges, both at home and abroad. Ambassador Bolton’s appointment as national security advisor will help the Trump administration advance policies that protect American security interests, while also supporting the aspirations of those around the world who are deprived of freedom and human rights. We wish our friend well. Joseph I. Lieberman, a former US senator from Connecticut, is chairman of United Against Nuclear Iran. Mark D. Wallace, a former U.S. ambassador to the United Nations for management and reform, is chief executive of United Against Nuclear Iran.