Former British Prime Minister David Cameron took the stage Tuesday night at Trinity University for the Flora Cameron Lecture on Politics and Public Affairs to call for a return to modern, compassionate conservatism. He laid out challenges the United Kingdom and United States face in light of a protectionist uprising in both countries.

Twice elected as leader of the Conservative Party, Cameron led the U.K. from 2010-2016. He championed global trade, but also the environmental movement and same-sex marriage. During his time as prime minister, Cameron worked to increase the number of women and minorities in his party. He stepped down in 2016 after U.K. citizens voted to leave the European Union in a history-making referendum best known as Brexit.

A career-highlight video introduced Cameron, ending with his departure from 10 Downing St. after the Brexit vote.

“Watching that is a bit like the film of the Alamo – no matter how many times I watch it, I wish there had been a different ending,” he said.

Cameron was candid about the referendum and the protectionist tone it set for the U.K. He related the Brexit vote to the election of Donald Trump, who has criticized U.S. trade deals such as NAFTA.

“[The United States] had to go and do something even bigger…” Cameron said.

In spite of these challenges to globalization, Cameron remains an “avowed optimist.” As evidence of the West’s potential for progress, he highlighted the advance of democracy in the decades following World War II, the technological revolution, and the continuing special relationship between the U.S. and the U.K.

For that potential to be realized, Cameron identified three challenges facing post-Brexit U.K. and the U.S. under Trump.

“My optimism tonight is not starry-eyed,” Cameron said.

First, he said, the countries must understand what lies behind the growing unease regarding globalization. While Cameron maintains that globalization built on free trade is the way of the future, he acknowledged the need for “a serious course correction.”

As the world became more interconnected post-WWII, the pace of change in industry and demographics resulted in large populations being left behind economically and culturally. The groups at an economic disadvantage are susceptible to extreme leftist ideologies, while the populations lagging culturally are susceptible to the extreme right, he said.

To extend the economic benefits of globalization, Cameron called for investment in education, particularly higher education, and raising minimum wages. Businesses would need to pay their workers and their taxes if they want to see continued growth.

To ease cultural anxieties, enforcing existing borders and immigration laws would have to go further than exclusionary policies like the executive orders recently signed by President Trump, Cameron said.

Cameron’s second challenge requires Western nations to engage and win arguments for the values that define our democracy.

Freedom under the rule of law is the foundation of democracy, Cameron said. A free election does not a democracy make. The government, its citizens, and industry must adhere to Constitutional laws, not the whims of the party or person in power.

For Cameron, the presence of Queen Elizabeth II, who has worked with 12 prime ministers and one quarter of all U.S. presidents in history, was a reminder of his small place in the continuum of history. Their weekly meetings kept him grounded.

“She had literally heard it all before,” Cameron said.

The U.S., after deliberately throwing off that same monarchy, replaced it with a Constitution meant to serve the same stabilizing purpose in the face of even the strongest personalities.

Free trade and Western democracy are worth fighting for, Cameron argued, pointing to the failure of protectionism and the wealth generated by free trade. He called for a strengthening of NATO as Russia inserts itself into the young democracies that were once part of the Soviet Union. Aggression into Georgia and the Crimean Peninsula have the Baltic states looking over their shoulders as Russian President Vladimir Putin makes plays to bring them home to Mother Russia.

Cameron acknowledged that Trump is right about the disproportional burden placed on the U.S. within NATO, but insisted that the alliance is still vital to prosperity.

“We will not make America great again by making Eastern Europe weak again,” Cameron said.

Cameron insisted that the U.K. was ready to contribute more to NATO efforts. He admonished Trump not to downplay the fundamental difference between the Russian and Western views of the world. Putin views the dissolution of the Soviet Union, one of the great Western triumphs, as the central tragedy of the 20th century, Cameron said.

The final challenge Cameron laid out was one of changing fashions in international affairs. This generation is seeing international aid going out of fashion, and the fight against Islamist extremism gaining momentum.

Decades of international aid have left many with “giving fatigue,” but the work is not done, Cameron said. With 750 million global citizens living on less than $2 per day and 120 million children unable to attend school, the task is great. Those not swayed by a moral argument to “love thy neighbor” should mind the security risk of illness, climate change, and mass displacement of people. Climate change and epidemics do not respect even the tightest national borders, Cameron said.

Islamist extremism, however, is not one of the security risks of global poverty, he said. It is born of a distorted religious agenda that crosses classes and crops up in countries that enjoy a variety of different relationships with Western democracies. The hijacking of Islam is an ideological battle that is hurting Muslims most directly, and threatening world security by extension, Cameron said.

The battle as Cameron sees it is in the hearts and minds of the global population. His vision for a modern, compassionate conservatism extends prosperity to places where extremism would cultivate poverty and oppression. To win that battle, Western democracies must demonstrate to the world not exclusionary self-interest, but appealing universal values.

“We must believe in them, work for them, and fight for them,” he said. “Then we really will be great again.”

Bekah McNeel is a native San Antonian. You can also find her at her blog, FreeBekah.com, on Twitter @BekahMcneel, and on Instagram @wanderbekah.