When conservatives and liberals find common ground, at times when we are not in the throes of a national emergency (e,g., Pearl Harbor, 9-11), bad things often happen. I will cite two examples, you may think of others.
My first example comes from the 1960s when we got rid of mental hospitals and, effectively, turned most insane persons into homeless wanderers, sharing our parks and sidewalks with the addicted. In this case the liberals believed we infringed the rights of the insane by involuntarily institutionalizing them.
Liberals argued everyone has a right to his/her/its own view of reality, essentially that all views are equally valid, including those of schizophrenics and raving paranoids. They argued for only warehousing the violent insane who pose a provable threat to others, this we now do in prison.
Meanwhile, conservatives saw all the money we were spending on mental hospitals, warehousing the incurable, and believed shutting the hospitals would save huge sums. The result is that, because the intent to establish community treatment centers was half-hearted, and using them voluntary, our homeless population grew by leaps and bounds.
The upshot of this collusion, we all ended up worse off. The homeless infest our streets and parks, pushing their stolen shopping carts, depositing their sewage where they exist, and panhandle everywhere. The insane are worse off, we are worse off, only those too elite to encounter them are better off.
The second example is illegal immigration. Liberals liked illegal immigration for a variety of reasons, some altruistic and some selfish. Sharing our wealth with the world's poor and downtrodden appealed to some, gaining new minority voters who normally vote with them appealed to all on the left.
On the right, the wealthy who fund conservative politics like a plentiful labor supply, as it makes unionizing difficult, provides plenty of cheap household help and holds factory wages down. They also like plenty of customers which illegal immigrants instantly become. Most end up on public assistance of multiple forms, and we pay for it.
Many argue for expanded bipartisan cooperation. More often than not, I believe it makes for bad policy, catering to the least admirable qualities of both extremes.
Trump's presidential victory represents a revolt of conservative voters against conservative fat cats, who fund Republican party activities and think tanks. Conservative voters heard Trump say illegal immigrants drove down wages, and understood the logic. He may be able to reverse the trend to ever-increasing illegal immigration. Now if someone would only promise to reinstitutionalize the insane and addicted....