It's been many decades now, but I still remember a piece of advice I got not long after entering Congress. It came in passing from a prominent journalist as we were talking about the bewildering array of issues Congress faced. Every day, he told me, I should ask myself a simple question: "What's the most important thing to be doing today?"

He was raising what may be the toughest problem in politics, though it's one you don't really confront until you take office: "What do you focus on at any given moment?"

Sometimes this is easy to answer. The 9/11 attacks occur, and the whole country turns to the agenda rising from that event. A river floods in your home district, and you put everything aside to deal with the problems created in towns and cities along its banks.

But in ordinary times, when we have the luxury of addressing every other pressing issue we face, legislators at all levels of government are confronted each day by a single, uncomfortable question: "Am I doing what I most need to be doing right now?"

Let's just look at the federal level, and start with the economic ones. At any given time, they're wrestling with:

- The economic growth rate;

- The need to provide broad-based economic opportunity;

- The need for investment in schools, hospitals, highways and other infrastructure;

- Annual deficits and a federal debt that has grown out of control.

Domestic policy challenges are no less daunting:

- Immigration and civil rights protections;

- The quality and availability of health care;

- The ost of higher education;

Third, there's a set of foreign-policy questions that seem without end:

- Climate change;

- Cyber-attacks and election meddling;

- Hostile powers like North Korea and Iran;

- Powerful adversaries such as Russia and China;

- The constant powder-keg of the Middle East.

Finally, the political challenges:

- Uncertainty about whether our political system can meet the challenges confronting it;

- The difficulty of arriving at a common set of agreed-upon facts, let alone the possibility of building political consensus;

- Deep political divisions and our inability to negotiate and compromise.

This is just a partial list. And even so, it's hard not to feel overwhelmed.

Moreover, these are the same problems we faced last year, and we'll face them again in 2020. The best we can do is manage them, chipping away year by year.

In a very real way, the depth and breadth of the many challenges we face show the depth and breadth of America's abilities and ambitions.

In short, my journalist friend was on the mark. Maybe the best you can do each day is ask yourself: "Am I putting my energy where it ought to be right now?" It's what makes governing such a bewildering, challenging job. It's also what lies at its heart.

Lee Hamilton is a senior adviser for the Indiana University Center on Representative Government; a Distinguished Scholar of the IU Hamilton Lugar School of Global and International Studies; and a Professor of Practice, IU School of Public and Environmental Affairs. He was a member of the U.S. House of Representatives for 34 years.