There are human resource challenges, too. Our K-12 education system includes some of the world’s best schools, but that excellence has been hard to replicate across districts and states with widely varying conditions. Our higher education system remains the world’s best, but costs and student debt are big problems. Health care reform has brought millions of people affordable, quality medical insurance for the first time, but we have wasted too much time fighting over efforts to repeal that progress when we should be fixing the problems that remain and preparing for the aging of our population. The future of undocumented immigrants — including the “Dreamers” and millions of people who are working hard and paying taxes — is uncertain at a time when our work force cannot grow without them; the birthrate among native-born Americans is barely at replacement levels. From Charleston to Charlottesville, we are reminded that the racial divide remains a curse that can be revived with devastating consequences. And the opioid crisis and its progeny, heroin and fentanyl, are killing and disabling Americans at a staggering rate. For several years we’ve known it’s a huge public health challenge, yet almost nowhere do we have the resources and organization necessary to turn the tide.

Finally, we have a serious set of security challenges, from nuclear proliferation, to terrorism, to climate change, to cybersecurity, the last of which may prove the most daunting because it puts all the systems we need to deal with the other problems, and our very democracy, at risk.

In spite of our overall economic progress since the 2008 crash, all these challenges have contributed to declining economic mobility, increasing political and social alienation and more personal insecurity for millions of our fellow citizens. These forces have increased our divisions, and make it even harder to recover our sense of common purpose.

The good news is that an aggressive effort to address our problems with known and affordable responses would bolster the strength of our economy and our communities through higher incomes, more upward mobility and greater security. Many cities and several states are proving it every day.