When, for superior motives, you are compelled to bribe an industry that would fail otherwise, you should not imagine that this industry is lucrative.

Frédéric Bastiat
Complete Works, Volume 7, pages 138 to 143 (in French)
Mémorial bordelais, October 25th, 1846

In this third and last letter, Frédéric Bastiat delves into the protection of the merchant navy and the arguments that are put forward. He does not consider them convincing and tells the merchants as well as anybody else: “always ask for freedom because you have no right to demand that the nation relinquish it to your advantage”. As Adam Smith had noted, there is a possible argument albeit not very plausible, which is that of national security. This argument is highly theoretical and liberals do not fall for it in general because it would also be necessary to prove the success of the stated goal and show that it is superior to alternatives. However, it follows a logical reasoning and thus deserves to be considered. What today’s quote tells us is that if this argument needs to be listened to, it does not make other arguments valid (supporting national labour for instance). 

Subsidies and other protectionist measures to support national security can be accepted only if the protected industry is loss-making while being absolutely necessary. Yet, a loss-making industry destroys value and such measures can be justified only upon acknowledging it. Therefore, any other reason that would make you believe the opposite must be rejected.