Part of why we plead for mercy for a whole people/nation at times is that when a nation begins to reject learning from God, we read in scripture, such as through the prophet Isaiah -- that God will at times choose to let a nation/people suffer in order to learn from their mistakes of choosing evil by hard experiences and suffering, for their own good:
He will not always hold back from allowing suffering in a nation when people in that nation do too many evils -->
4 “I will make mere youths their officials;
children will rule over them.”
5 People will oppress each other—
man against man, neighbor against neighbor.
The young will rise up against the old,
the nobody against the honored."
-- Isaiah 3 (and do read in full context of chapters 1 to 3 as a whole, and the message is even more emphasized)
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God looks to the real long run: that people truly repent of our very real evils, and He will helpfully allow those that even might repent to suffer plenty as that is extremely helpful to those of us that might repent to help lead us to finally repent...
This is a prime reason why God allows so much suffering in the world -- it makes a lot of people grow up and come to repentance and begin to treat others around them better...
So, at times, because He loves us, God will allow us to choose to follow evils like those advocated by Trump, because people need to learn by hard experiences and suffering the real consequences of ignoring His words to us and choosing evil.
We have to learn, somehow, and if we ignore scripture, we can only learn the hard way...by suffering.
The urge to follow the flesh, lusts/anger/evils is exactly one of Trump's main appeals to his followers -- such as that we should deport immigrants instead of loving our neighbors as ourselves.
A precisely opposite action to God's will for how we are to live:
"The foreigner residing among you must be treated as your native-born. Love them as yourself, for you were foreigners in Egypt. I am the LORD your God." -- Lev 19:34
(here quoted in red because this is literally God Himself speaking these words aloud)
As Christ also said in more detail:
31 “When the Son of Man comes in his glory, and all the angels with him, he will sit on his glorious throne. 32 All the nations will be gathered before him, and he will separate the people one from another as a shepherd separates the sheep from the goats. 33 He will put the sheep on his right and the goats on his left.
34 “Then the King will say to those on his right, ‘Come, you who are blessed by my Father; take your inheritance, the kingdom prepared for you since the creation of the world. 35 For I was hungry and you gave me something to eat, I was thirsty and you gave me something to drink, I was a stranger and you invited me in, 36 I needed clothes and you clothed me, I was sick and you looked after me, I was in prison and you came to visit me.’
37 “Then the righteous will answer him, ‘Lord, when did we see you hungry and feed you, or thirsty and give you something to drink? 38 When did we see you a stranger and invite you in, or needing clothes and clothe you? 39 When did we see you sick or in prison and go to visit you?’
40 “The King will reply, ‘Truly I tell you, whatever you did for one of the least of these brothers and sisters of mine, you did for me.’
41 “Then he will say to those on his left, ‘Depart from me, you who are cursed, into the eternal fire prepared for the devil and his angels. 42 For I was hungry and you gave me nothing to eat, I was thirsty and you gave me nothing to drink, 43 I was a stranger and you did not invite me in, I needed clothes and you did not clothe me, I was sick and in prison and you did not look after me.’
44 “They also will answer, ‘Lord, when did we see you hungry or thirsty or a stranger or needing clothes or sick or in prison, and did not help you?’
45 “He will reply, ‘Truly I tell you, whatever you did not do for one of the least of these, you did not do for me.’
46 “Then they will go away to eternal punishment, but the righteous to eternal life.”
-- Christ Jesus, Matthew 25
So, wishing that none would perish in their sins (2nd Peter 3:9), God will at times let a people suffer for their evils to help them repent (those willing to repent).
So, this is why we at times beg for mercy for our nation, for the profound evil of mistreating the foreigners that come to our land by seeking to deport them back to their nations of origin (where some will be murdered according to death threats they already received from gang in their original nations, and that's why some fled to America.... and other fled here due to desperation from lack of all chances for honest work to make a living....)