1. Weight of circumstances — Strong will argument
Argumentation by the weight of circumstances invokes the nature of things or the external constraints, as imposing a deterministic solution on a social issue. The decision is presented as causally determined by the context: “facts leave us no choice”, “what happens in the world forces us to do so”.
In 1960, Charles de Gaulle, the President of the French Republic, held a referendum on the question of the independence of Algeria, with which France had been at war since 1954. He urged the people to vote for Algerian independence.
No one can doubt the extreme importance of the country’s response. For Algeria, the right granted to its peoples to dispose of their fate will mark the beginning of a whole new era. Some may regret that prejudices, routines and fears previously prevented the assimilation of Muslims, assuming it were possible. But the fact that they constitute eight-ninths of the population, and that this proportion continues to grow in their favor; the evolution begun in people and in things by the events, and prominently by the insurrection; and, finally, what has happened and what is going on in the world — make these considerations chimerical and these regrets superfluous.
Charles de Gaulle, December 20th 1960 Speech.
The strong will argument denies precisely this determinism: “where there is a will, there is a way”. In May and June 1939, the Belgian, British, French and Netherlands armies were totally routed by the German Nazi armies. In a situation that appeared desperate to many, General Charles de Gaulle rejected the armistice that Marshal Petain had just signed with the German Nazi enemy, and from London launched on the BBC his call to continue the fight:
Of course, we were subdued by the mechanical, ground and air forces of the enemy. Infinitely more than their number, it was the tanks, the airplanes, the tactics of the Germans which made us retreat. It was the tanks, the airplanes, the tactics of the Germans that surprised our leaders to the point of bringing them to where they are today.
But has the last word been said? Must hope disappear? Is defeat final? No!
Believe me, I speak to you with full knowledge of the facts and tell you that nothing is lost for France.
[…] Whatever happens, the flame of the French resistance must not, and will not be extinguished.
Charles de Gaulle, Text of the Appeal of June 18, 1940
Major political decisions combine the two forms of argumentation.
2. Naturalistic argument
In law, naturalistic argument refers to the hypothesis of an impotent legislator arguing that it is impossible to legislate in certain areas, or of a judge who waives the application of the law on the pretext of special circumstances, S. Juridical Arguments.
The naturalistic argument is also exploited in the field of religious law; Luther uses it in connection with the prohibition of the marriage of priests by the Pope of the Roman Catholic Church. According to Luther, most priests “[cannot] do without a woman”, at least for their household:
If therefore [the priest] takes a woman, and the Pope allows this, but will not let them marry, what is this but expecting a man and a woman to live together and not to fall? Just as if one were to set fire to straw, and command it should neither smoke nor burn.
The Pope having no authority for such a command [forbidding the marriage of priests], any more than to forbid a man to eat and drink, or to digest, or to grow fat, no one is bound to obey it, and the Pope is answerable for every sin against it.
Martin Luther, Address To The Nobility of the German Nation, 
A priori, the naturalistic argument has little to do with the naturalistic fallacy, which systematically values the natural, S. Fallacious (2). However, the accusation of fallacious naturalism might serve to refute the argument of the force of circumstances.
 http://fresques.ina.fr/de-gaulle/fiche-media/Gaulle00063/speech-of-20-December-1960.html (20-09- 2013).
 http://lehrmaninstitute.org/history/index.html (01-20-2017).
 Quoted after http://sourcebooks.fordham.edu/mod/luther-nobility.asp, (01-20-2017).