Sister Susan Francois, 46, of the Sisters of St Joseph of Peace religious order, sent her first prayer to Donald Trump's official @POTUS account just a few days after he was inaugurated in 2017.
"I didn't expect it to make a big splash. But that fact that it was public and that I committed to it every day means I have to do it, even if I don't want to.
"It's been the hardest spiritual practice I've ever committed to."
Francois's tweets usually encourage Mr Trump to be mindful of Christian values but also sometimes highlight policy suggestions.
Her 657th tweet stated: "Dear @POTUS, as you represent nation on global stage at #G20, praying that you keep in mind and heart the common good of all future and present generations over ego, personal agenda, or special interests."
She has also been critical of Mr Trump's decisions.
In her 654th tweet she said she was praying for the president "but unable to find kind words" as she opposed his anti-immigrant position.
"I am angry at blatant disrespect & outright violence against human beings seeing refuge at border.
"I am outraged that partisan politics trump humanity. Good thing Jesus understands righteous anger."
Dear @POTUS, 665 days later still praying you experience and understand yourself (and everyone else, even those you disagree with or deem unworthy of respect) as a beloved child of God and act accordingly. This mind/heart shift can be transformative #dailytweet— Sister Susan Francois, CSJP (@susanfrancois) December 8, 2018
Francois - who describes herself as a "Gen X Catholic Nun" in her Twitter bio said she tweets to the official presidential Twitter account instead of Mr Trump's personal account because official tweets are archived.
She explained: "From my academic research on resistance as a response to injustice, it is important for consistency and for history to know that ordinary people didn't look away.
"I wanted it to be a record of history that a Catholic sister wanted to tweet a nonviolent prayer at the president."
Mr Trump has not responded to any of the tweets.
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