Democrat and sane.
Republican and sane.
Political and sane.

Polar? or dualistic? Very little we know does not have an opposite.

Obverse reverse
Slick and rough
good enough

Combine them and you're into oxymorons, mulish morons, bullish morons...

Polar? Spectrums all along the same element but at opposite ends and all at once, like:

Sweet and sour
Joy and sorrow
Laugh 'til you cry
Pleasure and pain
a generous thief
a tight philanthropist

Killing me softly, perhaps with the kiss of death.
Infinitely finite.
Frozen flames.
The red hot vacuum of space
A neat pig
A filled hole
On and on we go