"As long as the roots are not severed, all is well, and all will be well, in the garden" I will speculate that what is morally unacceptable to the public sets a baseline to the behavior of a president and to the behavior of the country.
I'm not going to suggest that we need a Holy Roller leading the country, that was tried with G W Bush and he started two major wars, and we lost both. But what the best religious people, of whatever kind including the top atheists, and Buddhists agree is wrong, generally is wrong. We should not have put launchers suitable for tomahawk nuclear armed missiles in Poland and Romania pointing at Russia. That was very impolite.
I took 'the roots' to represent the basis of society, the people who support society, and supply the water and the minerals. I guess then Congress and the President would be the heartwood, which does nothing useful and is often rotten.
The actual leaders are perhaps analogous to the leading shoots at the top of the tree; perhaps Buddhist, Christian, Hindu or other religious leaders, or individuals such as: Noam Chomsky, Richard Dawkins, Jordan Peterson, Christopher or Peter Hitchens, Eric or Bret Weinstein, Profs Richard Wolff and David Harvey, Jonathan Haidt, and a multitude of others, we live in a time when we have access to an Internet full of great intellectuals and leaders.
I would suggest 'the roots' are the farmers, truckers, housebuilders; mothers - everyone who supports society, but the analogy gets less obvious in the other parts of the plant. For example, it appears that countries usually die from the top down. The rot starts with Congress accepting bribes from lobbyists, and spreads through a long-standing Senator who becomes President and his friends and relatives, making ridiculously bad decisions to funnel money into corrupt ventures for kickbacks. Like it did in pre-Revolution France, the country was rotting from the top down, where the Queen was sufficiently insulated from real life to give the advice when told the peasants had no bread to say: 'let them eat cake'.
Unlike many plants where the rot begins in the roots, in nations the rot usually starts at the top. In the Roman Empire a corrupt or foolish Emperor led the nation into ruin while a good Emperor helped rebuild it.
