Sen. Joe Lieberman (I-Conn.) delivered his final speech from the chamber floor yesterday. Toward the end of his remarks, he talked about foreign policy, which has been the defining subject of his career. To his colleagues and the entering freshman senators, he implored:

Do not listen to the political consultants or others who tell you that you shouldn’t spend time on foreign affairs or national security. They’re wrong. The American people need us, the Senate, to stay engaged economically, diplomatically and militarily in an ever-smaller world.

Do not underestimate the impact you could have by getting involved in matters of foreign policy and national security — whether by using your voice to stand in solidarity with those who are struggling for the American ideal of freedom in their own countries across the globe, or working to strengthen the foreign policy and national security institutions of our own country, or by rallying our citizens to embrace the role that we as a country must play on the world stage, as both our interests and our values demand.

None of the challenges we face today, in a still dangerous world, is beyond our ability to meet.

Just as we ended the ethnic cleansing in the Balkans, we can stop the slaughter in Syria. Just as we nurtured the democratic transition after communism fell in Central and Eastern Europe, we can support the forces of freedom in the Middle East today. And just as we were able to prevail in the long struggle against the Soviet Union during the Cold War, we can prevail in the global conflict with Islamist extremism and terrorism that we were forced into by the terrorist attacks of September 11, 2001. But all that too will require leadership in the United States Senate. It will require leaders who will stand against the siren song of isolationism, who will defend our defense and foreign assistance budgets, who will support, when necessary, the use of America’s military power against our enemies in the world and who will have the patience and determination when the public grows weary to see our battles through until they are won.

Certainly, these admonitions reflect Lieberman’s innate optimism.

Sens. Joe Lieberman, right, and John McCain. (Hassene Dridi/Associated Press)

Truth be told, most senators don’t get much praise for foreign policy, but Lieberman’s career is a reminder that there is plenty of time to tend to domestic affairs as well. And while home-state constituents may not fully appreciate the importance of foreign policy, each senator takes the oath of office to defend the Constitution “against all enemies, foreign and domestic.” That responsibility can and should be shouldered by those who have the knowledge, temperament and interest in engaging in the protection of our country and its values. So, in other words: Don’t neglect constituent concerns, but American foreign policy needs attention.

As for Lieberman’s optimism about the world, let’s say it is a work in progress. We really don’t know whether Arab countries will embrace democracy, the rule of law and respect for minorities with the speed and completeness of Western Europe and much of Central America.

Moreover, there are no obvious candidates who meet Lieberman’s pleas for leaders who “will stand against the siren song of isolationism, who will defend our defense and foreign assistance budgets, who will support, when necessary, the use of America’s military power against our enemies in the world and who will have the patience and determination when the public grows weary to see our battles through until they are won.” Sen. Robert Menendez (D-N.J.), who has worked diligently on Iran, may be one. Sen. Ben Cardin (D-Md.), who championed the Magnitsky bill on Russian human rights, is another. And Sen. Robert Casey Jr. (D-Pa.) has joined in a number of bipartisan resolutions. But does anyone have the passion or interest needed to go up, when needed, against the White House and sustain defense spending? Again, I am less than certain.

Moreover, Lieberman was speaking, appropriately so, to his colleagues. But while the Senate has a constitutional role to play in national security on treaty approval, confirmations and spending, it is the executive branch that has the laboring oar. So the real question should be directed to President Obama: Will he “stand against the siren song of isolationism . . . defend our defense and foreign assistance budgets, and . . . .  support, when necessary, the use of America’s military power against our enemies in the world”? Unfortunately, he has already shown that he does not have “the patience and determination when the public grows weary to see our battles through until they are won.”

The Senate cannot initiate action in Syria. It cannot, on its own, prevent “devastating” cuts to defense. It cannot make more credible the military option with Iran. These the president must do. And, most worrying, it is not even clear that he knows how to or wants to assert American power and values in the world. 

I would implore Republicans contemplating a 2016 run to spend time, lots of it, with Lieberman and to listen carefully to his worldview, insights and understanding of the connection between human rights abroad and American security at home. They may not agree entirely, but it would be among the most productive activities they can undertake before setting out to offer themselves as candidates for commander in chief.

To say Lieberman will be missed is a gross understatement. To say he can be replaced is ridiculous. But to hope he is emulated is the fond wish of those who believe in the Truman-JFK-Scoop Jackson tradition about which he often spoke so eloquently.