knee-jerk reaction

The club threatened further legal action if there was a "knee-jerk reaction".

There would be no knee-jerk reaction, no continuation of the short-lived spells of Giovanni van Bronckhorst and Michael Beale, no throwing good money after bad in a frenzied pursuit of their city rivals.

While you’ve been chewing over this question for more than a year, of whether the Alien Enemies Act could really be exploited in some fashion to do either mass detentions or mass deportations, as Trump is promising, there’s been a pretty knee-jerk reaction in the legal commentary of: This could never stand, it’s not an invasion, no declared war, it just couldn’t happen.

I am not getting any sense there will be a knee-jerk reaction.

Yi called Proposition 36 “a knee-jerk reaction” to crime statistics.