It is “ideologically extreme; scornful of compromise; unmoved by conventional understanding of facts, evidence and science; and dismissive of the legitimacy of its political opposition.” Taking the debt ceiling hostage, for example, is not the action of a conservative party. It’s the action of an extremist party, willing to risk economic Armageddon for trivial policy changes.
This is, I think, due to the conservative media ecosystem and the perverse incentives of minority parties in the US constitutional system. Conservative media is ruled by liars, con men and charlatans who actively profit from having Democrats in power, and who whipped the Republican base into a seething frenzy after the election of Obama.
Matters of policy have dissolved almost completely into the froth of tribal resentment and Obama hatred, which produced a huge class of new Republican house members who were slavering to attack the president with whatever tool was closest.