If there was still any hope in Europe that Donald Trump might turn out to be less disruptive than he promised, the first weeks of his presidency must have put such hopes to rest.

It’s been less than two weeks and Trump has already disheartened America’s allies in Asia by withdrawing from the Trans Pacific Partnership, giving China a golden opportunity to take charge of regional economic integration; offended Australia and Mexico but hinted at improved relations with Russia, and banned Muslim immigrants and refugees from seven countries — including those who were previously approved for a visa — making a mockery of the rule of law and betraying a complete lack of compassion.

Imagine the damage he can — and will — do in four years.

Theresa May, the first foreign leader to visit Trump in the White House, seems to believe she might exert a moderating influence on the new president. This is wishful thinking. Donald Trump has changed his mind on everything from abortion to health policy, but the way he views the world has remained remarkably stable through the years. Even when Ronald Reagan was president, Trump complained that America was being played for a fool by other nations, including its friends. He sees international relations as a zero-sum game and believes the affairs between states are guided by quid pro quo as opposed to generosity and trust.

This is, of course, quite the opposite of what Europe believes.

Here are four things it can do to defend the world the West has made.

1. Circle the wagons

Now is not a time for infighting. There are two issues which could divide Europeans in the near term: Brexit and Greece. Both should be resolved amicably.

The remaining 27 member states have so far held the line on the indivisibility of Europe’s four freedoms: the free movement of capital, goods, services and people. The alternative is an unraveling of the compact that holds the EU together.

Theresa May has accepted that the United Kingdom will not be able to stay in the single market if it wants to regain full control over its immigration policy.

But there are others who may try to use Brexit as an opportunity to renegotiate those freedoms. The Dutch Labor Party, for example, wants to throw in a reform of the free movement of labor in order to stop what it regards as unfair competition from Eastern Europe.

They may have a point, but this would needlessly complicate and possibly the Brexit process. Europe needs a clean break.

Greece needs a break, period. The exasperation of northern creditor states is understandable. The Greeks continue to drag their feet on economic reforms and waste no opportunity to weasel their way out of spending commitments. But soon the country will have been in crisis for a decade. If this wasn’t enough to change the Greek mentality and make them more like Germans or Finns, nothing will.

A generation of Greeks has now come of age with diminished prospects in life and no illusions about the EU. The bloc must make clear its solidarity still extends to the Aegean Sea, for example, by forgiving a portion of Greece’s debt.

Especially because the illiberal world order Trump seeks to preside over begins on Greece’s doorstep: Turkey’s president, Recep Tayyip Erdoğan, has revealed himself to be an autocrat who will undoubtedly make life more difficult for Europe in the years to come.

2. Double deterrence

Brexit clears the way for closer military cooperation in Europe.

The United Kingdom has long prevented the French and other nations from developing a foreign and security policy independent of NATO and the United States. By opting out of the EU, it has lost its right to veto such plans.

Similarly, Madeleine Albright’s famous “three Ds” — no duplication of NATO, no decoupling from NATO, no discrimination against NATO countries, like Turkey, that are not in the EU — are now moot. It is America, not Europe, that has declared NATO “obsolete”. It is Europe, not America, that will suffer the consequences. If Trump won’t fight for Estonia, Vladimir Putin must know that Europeans will.

That doesn’t mean deliberately weakening NATO further. It rather means adding a second layer of deterrence.

Concretely, this could involve more asset-sharing (the Dutch-made HNLMS Karel Doorman, for example, is operated by both the Dutch and German navies), joint development and procurement (like the Eurofighter), joint air and naval patrols in the Baltic Sea area together with non-NATO Finland and Sweden, and the deployment of Western European “tripwire” forces to the EU countries on Russia’s border.

3. Uphold liberal norms

Trump has proposed to usher in a new era of isolationism. Europe must reaffirm its belief in open borders and shared prosperity.

That doesn’t mean the end of national sovereignty. European leaders need to avoid the mistake Democrats in the United States made by taking multiculturalism and free trade for granted. Immigration creates real frictions, not just prejudices, and globalization has left some in the cold. But European countries, with their traditions of social democracy, are well-placed to soften the edges of a system that has on balance made the whole planet more peaceful and prosperous.

We are about to rediscover what closed borders and every-man-for-himself mean in practice. Trump’s Muslim ban is the most egregious example. His withdrawal from the Trans Pacific Partnership (TPP) and plan to build a Mexican border wall, possibly financed by a tariff on imported goods, are no less damaging in the long term. It would be one thing if America shot itself in the foot, but such policies will leave everybody worse off.

Europe can lead in a different direction. It should update its free trade agreements with Chile and Mexico — two countries that would have been in TPP — and breathe new life into the trade talks with Mercosur. National parliaments ought to ratify the Comprehensive Economic and Trade Agreement that was recently signed with Canada. Europe must continue to arbitrate disputes through structures like the International Court of Justice and the World Trade Organization, which Trump’s America may seek to circumvent. And it has to uphold the rights of refugees, which the United States are blatantly violating.

4. Soft power isn’t soft

Donald Trump is showing the world an ugly side of America. He is giving credence to strongmen who say democracy doesn’t produce better government. He is giving credence to cynics who claim America’s promotion of human rights is insincere. America’s example as a boisterous but functioning democracy, with a free and fearless press, with religious freedom and pluriformity, has suddenly gone.

Europe may not be the next city on a hill. But the EU has inspired democratization and liberalization in Eastern Europe and regional integration in Latin America, West Africa, the Persian Gulf and Southeast Asia.

More recently, we saw in Ukraine’s Euromaidan uprising that the EU means something more than budget rules and food safety standards for the people who live outside it.

If we are to avoid falling back into the traps of autarky and suspicion that pits nation against nation, then Europe must stand up for what’s right.

Norms matter. Compassion, human rights and the rule of law matter. Trump doesn’t think so. Let Europe prove him wrong.