A free people can never get tired of doing what is necessary to preserve their freedom and national security.
So, what I think people are actually tired of is "those involved in war who are making no effort to win." The US totally, unconditionally defeated 2 major economic powers in world war two in a little more than 3 years. We went all out toward victory.
We've been piddling around with Iran, Iraq, Afghanistan and the like for two decades now. THAT is what they're tired of. It is immoral to shed the blood of your troops in causes to which you aren't committed.
The problem here ... is ... you’re not talking about a majority of the population. Things are changing from the old days.