I like to think you know people are not serious when they always have the same solution – no matter what the problem.
For instance there is a faction in the Republican party who think that whatever the problem the solution is to cut taxes. If you are running too big a surplus the solution is to cut taxes. If you are running a deficit the solution is to cut taxes. If you are fighting a war the solution is to cut taxes. If you face global warming the solution is to cut taxes. These people can be effective political operators but are useless at furthering the intellectual debate.
There are similar groups who think the solution is always more government regulation.
Puerile arguments exist on all sides of politics.