Washington ( CNN ) -- Former Secretary of State Henry Kissinger used a short speech at the State Department on Wednesday to joke about the prospect of Hillary Clinton running for President in 2016 . Standing on stage with five other former or current secretaries of state , Kissinger -- who served as secretary of state under Presidents Richard Nixon and Gerald Ford -- highlighted the work of diplomats and foreign service officers as he spoke at the groundbreaking for the United States Diplomacy Center , a museum set to honor diplomatic work . He then , however , dropped a slight joke about the prospect of Clinton running for president . `` We all know that we will never do anything more challenging in our lives than to serve these objectives , '' Kissinger said . `` I would say all of us , except one . '' Clinton , who served four years as President Barack Obama 's top diplomat , is widely considered the frontrunner for the Democrat 's presidential nomination in 2016 . She has hinted at thinking about running for the job and has a cadre of groups organizing around the possibility that she runs . Joining Kissinger and Clinton on stage for the groundbreaking were former secretaries James Baker , III , Madeleine Albright , and Colin Powell -- along with current Secretary of State John Kerry . During her short remarks , Clinton heaped praise on her colleagues and told the audience that Kissinger has `` written the book on diplomacy . '' While Kissinger 's joke was not an obvious joke about Clinton , the former top diplomat has been known to tease his successor about running for president . Shortly after Clinton left the State Department in 2013 , Kissinger gave a nod to Clinton 2016 while presenting an award to the former first lady . `` At least four secretaries of state became president , '' Kissinger joked during remarks at the annual Atlantic Council awards dinner in Washington . `` And that sort of started focusing my mind even though there was a constitutional provision that prevented me from doing it . I thought up all kinds of schemes to get around that . '' Then , adopting a more serious tone , he continued . `` I want to tell Hillary that when she misses the office , when she looks at the histories of secretaries of state , there might be hope for a fulfilling life afterwards . '' Clinton did not directly respond to Kissinger on Wednesday , but did do so in 2013 . `` When I became secretary of state , I spent a lot of time thinking about my illustrious predecessors -- not primarily the ones who went on to become president , '' Clinton said to laughter . Kissinger recently told NPR that although Clinton `` would be a good President , '' he would still vote for the Republican nominee . CNN 's Mary Grace Lucas contributed to this report .
Kissinger used a short speech on Wednesday to joke about Clinton 2016 . He appeared with five other secretaries of state . Kissinger said for `` all of us , except one '' the job was the most challenging of their lives . He has told NPR that Clinton `` would be a good president '' but he 'd still vote Republican .