"Radical Islamic Terrorism must be stopped by whatever means necessary! The courts must give us back our protective rights. Have to be tough!"

This was President Trump's Twitter reaction to the two terrorist attacks in Catalunya last week. The more deadly attack, which killed 13 and injured 100 people, had taken place Thursday on La Rambla, the pleasant tree-lined pedestrian mall in Barcelona, Spain that tourists flock to and locals enjoy.

Trump's tweet is open to interpretation. What did he mean with the words "by whatever means necessary," and precisely what "protective rights" was he referring to? One could take it as a simple expression of determination to tighten immigration policy and restore Trump's right to set it after a number of court decisions throwing it into question.

Border security can and should be tightened. America's "in door" is the best place to screen out terrorists, and if that's what Trump meant, we applaud him.

We hope Trump does not mean a curtailment of constitutional liberties, or to imply that courts have taken away too much enforcement power by upholding those liberties. In that context, it could mean he believes further intrusions are justified in the face of an obdurately nettlesome threat.

It is appalling that terrorists have killed so many people and caused so much panic. Let's not allow them also to rewrite our Bill of Rights, which is one of their goals.

Between the heightened hassle at airports, including the occasional ban on laptops, the collection of cellphone data, and the illicit use of the foreign surveillance apparatus to collect and store information on citizens, the federal government has already gone much further than most of the public likes.

Many proposals under discussion would go even further. There are, for example, lawmakers who want to strip rights from people whose names are merely placed on a government no-fly list.

It is important not to react reflexively every time another attack occurs by encouraging more and more questionable surveillance and search practices, limits on the First and Second Amendment, and similar expansions of the police state. Terrorists count on such a reaction; it is part of their plan to provoke western societies to become less open and less free.

An article by an al Qaeda terrorist last week articulated a related idea in his latest threatening message. The goal of the new wave of terrorists, as Ibrahim al-Asiri put it, is to force an "increase in security forces and labor hours, purchasing sophisticated equipment, establishing new special units to specifically face these threats and reinforcing counterintelligence efforts to disrupt any attempt of another attack whatsoever." As the Washington Examiner's Tom Rogan noted, al-Asri even favorably mentioned the potential of terror attacks to raise insurance premiums.

All indications are that the terrorists are moving away from spectacular attacks that cause mass civilian carnage for its own sake, and toward smaller, low-budget attacks that erode the sense of safety and the simplicity of life in the West. Last week's attacks in Barcelona follow that pattern, as do earlier automobile attacks in Nice, Paris, London, Berlin, and Stockholm, as well as the Islamic State massacres in Orlando and San Bernardino.

Instead of just killing, today's crop of terrorists is seeking to make western life unlivable, to kill in ways that heighten paranoia and sabotage the openness and economic viability of civilized freedom. If you can't even feel safe on La Rambla, then Barcelona is transformed from a beautiful and vibrant destination city into a place where everyone has to watch their back.

At any moment, whatever city you're in, that car you see just might be the one that plows into the crowd you're standing in. That's what the terrorists want you to worry about constantly.

The terrorists do win if we do what they want — to say so is an obvious tautology — and they want us to sacrifice civil liberties to stop them.

The Spaniards this week understood this, and so we cheered when the police, while were hunting and killing the terrorists who had murdered 13 people, nevertheless reopened La Rambla. That open, bustling boulevard on Friday night embodied the very things the terrorists wanted to kill; free people were enjoying themselves, strolling hand in hand, drinking at cafes, and making it plain that they would not allow themselves to be intimidated.

To adapt an Obama-Biden campaign slogan, La Rambla is alive, and the terrorists are dead. It was a winner. We hope President Trump takes it to heart and responds by keeping civil rights alive while killing as many terrorists as possible.