Many sources here and in Europe have wondered at rightist parties making positive comments about Vladimir Putin of Russia. How, they've asked, can you admire someone so obviously an opponent of your national interest?
I think perhaps I have stumbled across an answer, if not perhaps the answer. Putin is admired for being an unabashed advocate for his own country. Putin acts for Russia the way rightist parties wish their own national leaders would act for their countries.
In America it is widely reported Putin has played a relatively weak hand well, whereas Obama has played a relatively strong hand poorly. European nationalists see Putin as having played Russia's weak hand well whereas Angela Merkel has played Germany's strong hand poorly.
When Trump says he believes Putin a strong leader he doesn't mean one America will be fond of, but one Russia is fond of. Trump aspires to be similarly popular among Americans as Putin is among Russians and for the same reasons.
It is entirely possible to admire an enemy's skill while opposing his goals, much as northerners admired the generalship of Robert E. Lee during our Civil War. He played the South's weak hand skillfully on behal of secessionist slaveholder goals with which they did not agree.
Singing "Every hand's a winner and every hand's a loser," Kenny Rogers made this point - winning with a strong hand should be easy even if some blow it, the real skill is winning with a weak hand.