President Donald Trump seemingly doesn't care if you're part of his party ... as he recently leaked GOP Sen. Tom Cotton's personal phone number on Truth Social.

Taking to his own social media platform ... the prez criticized Tom for single-handedly blocking his Sunshine Protection Act in the Senate.

The legislation -- that Trump referred to as the "We Don’t Want to Change Our Clocks Twice a Year Act" -- would make Daylight Saving Time permanent all year 'round.

In making his case for the bill that would avoid the need to change clocks twice a year ... Trump argued ... "It’s very expensive for our Nation where you have high and dangerous steeples to reach, like on churches and municipal buildings."

Trump said that having more afternoon sunlight is beneficial for the PGA TOUR, golfers, tennis players, hunters, and farmers.

Urging his followers to "LOCK THE CLOCK!" ... Trump ended his rant by posting Tom's real-life cell phone number and urged people to contact him directly -- what could go wrong?!