The main significance of the PATCO strike in $1981$ was that it

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marked a turn in U$.$S$.$ labor relations toward much more adversarial relations between management and labor.

resulted in the fragmentation of the labor movement by splitting key unions such as the Teamsters and SEIU from the AFL$-$CIO.

made it lawful for employers to hire permanent strike replacements during an economic strike.

heralded a new era of labor$-$management peace in the US