The term "coalition of the willing" refers to a form of international cooperation in which countries outside the framework of the Alliance voluntarily engage in a specific military or security mission.
This is nothing new. An example was the coalition of the willing during the 2003 intervention in Iraq. (And today we see that the second war by a coalition of the willing in the Gulf did not bring greater security or stability to the region.)
One advantage cited in favor of coalitions of the willing is the speed of action. When it is procedurally impossible to reach a decision by the entire Alliance, certain member states activate themselves—states among which agreement can be reached quickly. Such a process cannot be prevented. It is every country's right to choose its own path of engagement, even outside the framework of an international organization.
However, such an approach is generally dangerous—for ourselves as well. First and foremost, it demonstrates NATO members’ inability to stick together. The Alliance is perceived as fragmented. It represents a path toward erosion of the principle of collective defense, which is the cornerstone of NATO, enshrined in Article 5 of the North Atlantic Treaty: the principle of "one for all, all for one." Either we are allies, or we are not.

A coalition of the willing is a tool for bypassing democratic processes and international legitimacy. Interestingly, in the Czech political context, the governing coalition parties advocate for such coalitions while simultaneously opposing any change to the unanimity rule within the European Union’s Common Foreign and Security Policy, so that no one could go around us. One simply cannot look credible while supporting both positions—that is, defending the unanimity principle while promoting coalitions of the willing. One must choose either one or the other.
The political danger of leaning toward coalitions of the willing may affect us in the future too. What will we do if we ourselves become the target of an attack—perhaps a cyberattack—and invoke our right to collective defense under the treaty, only to be advised by our allies to seek out a coalition of the willing instead? Whom would we find then?
Cyril Svoboda