That was a limits problem to which several negotiated outcomes were tried, none of them successful. Then Bolivians tried a policy of encroaching military forts

That was a limits problem to which several negotiated outcomes were tried, none of them successful. Then Bolivians tried a policy of encroaching military forts in the Chaco region. It was a matter of time before a Bolivian patrol would clash with a Paraguayan patrol. That's how happened. I wouldn't say it was stupid more than any other border wars are stupid.