For the record, Pétain had a pretty good point at his trial. He did not intrigued with the Germans to be nominated.
He was recalled by the Third Republic and became Président du Conseil because the Président asked. (On the other hand, Laval doubled down-after being casted out of the government in december 1940, he conspired with Germans to return)
Pétain wasn't exactly "recalled" by the Republic, because he did not stopped to serve it during the inter-war era (in military, academic, diplomatic, governmental missions) up to the moment he decided to make his coup.
Reynaud, the President of the Council of Ministers (the head of government), and Lebrun, the President of the Republic (the head of state), named him as Vice-President of the Council of Ministers, hoping that they would get the flamboyant hero of Verdun who promised, back then, about Germans that
they'll will not pass... (a motto latter adopted by Spanish Republicans), alas for Reynaud, what they get in the government, was the stubborn opponent to any war with Germany, even when the war was already there, the herald of defeatism, the wall against all solutions whose aim would be to pursue the war, the man who would paralyse the action of the government.
As Pétain did oppose to anything that didn't implied the unilateral surrender to Germany, the solution found by Reynaud was to let the burden to Pétain so he would seek to get his armistice with Nazi Germany. Reynaud was so confident that German demands would be so unacceptable for France's honour that he was sure that Pétain's suggested option could only end being sanely ruled out and with it the whole defeatist faction of the government. He was persuaded that he would then be called back as President of the Council and that it would only leave one path to follow: pursuing war. So he gave his resignation to Lebrun, suggested him to name Pétain to succeed him as the next President of the Council and -as he wisely figured- German demands were indeed way too much unacceptable for French honour...
... but Pétain not only accepted them: he asked to soldiers to stop fighting even before negotiating armistice terms, while there was still fightings! Then he made his institutional coup and destroyed the Republic in Mainland France. Why? Because, like many military top officers and even like a part of the parliamentary right-wing of the time, Pétain was a silent but convinced opponent to the Republic and a French defeat against German was seen being very desirable for them as it would allow to put an end to Republic's revolutionary values of Human Rights, fundamental liberties, popular sovereignty,
&c. and to reform, to rebuild the old society of order, labour and obey. The defeat was a
divine surprise, to quote Maurras, one of the major political thinker of that political family.
Not that Pétain and his followers were nazi or fascists: those two political family were and still are quasi inexistent in France... French fascism only achieved to take some control in very exceptional circumstances of 1944, when Vichy collapsed, Germany invaded the so-called Free zone and the Militia took control over what it could). Before that very short and specific moment, French fascists showed their disdain and their disappointment of Vichy's Regime, whined that it was too much reactionary.
Just like Franco who received, in 1939, credence letters from Pétain, then Ambassador of France in Spain, Pétain and Maurras believed in counter-revolutionary values. This counter-revolutionay right, is
the right-wing, whose main thinkers include Chateaubriand, Burke, Bonald, Maistre... After the Franco-Prussian war, with the wind of nationalism -that is to say ethnic nationalism- altered all right-wing political families. For example the authoritarian and popular right, which was Bonapartist in the old times, became Boulangist after the Franco-Prussian War, Rocquist during the inter-war and Gaullist in the After-war.
Similarly, nationalism inspired the old counter-revolutionary right, especially under Maurras thought and his Integral Nationalism. This is this thought that was experimented by Pétain between 1940 and 1944. 1829-1830 and 1940-1944 are the sole cases, since the French Revolution, were this political family effectively controlled the national executive body.
Hence, the idea that Pétain would had tried to save France
from German invasion is, in my humble opinion, incorrect. What he tried to do, was to save France from French Revolution dregs and from Republican vices (such as liberty, equality and fraternity)
through German invasion! Through a German invasion which allowed him to establish a new, non-republican, regime found, among others, on the values of labour, family and fatherland.
