Trump tried to overthrow the U.S. Government. Why isn't he in Gitmo? ?

"TRIED TO OVERTHROW THE US GOVERNMENT".  The strongest army in the world couldn't do that, let alone one man.

Watch on MSNBC or CNN (perhaps C-SPAN) the actual trial in the Senate today, Ferfie.  The House-passed second Impeachment (indictment) of Donald Trump on January 13th while he was still President is now being tried. The charge involves Trump's attempted overthrow, as your question mentions, a.k.a., Insurrection attempt that deliberately incited mob violence against a co-equal branch of our three-branch people-elected government.  The January 6th breach of our people-owned Capital Building while a Joint Session to formally receive, then record the 50 states' certification of voting outcome (making Joe Biden the 46th President) was underway, but spoiled-brat traitor Donald Trump incited a deadly riot for which the trial is designed to hold him accountable, preventing him from ever holding any taxpayer-funded public office and also costing him and the Trump family any taxpayer-funded post-Presidency perks (like the $1M per year for travel for wife and grown kids).  

Once 67 Senators vote "guilty" (we might have to LOBBY to get the Republican Senators to follow the rule of law), then Trump has had to face the consequences of his abuses of power that resulted in deaths and many injuries.

Trump did not attempt to overthrow the United States government Trump attempted to stay president there's a big difference there.

No.  Hillary Clinton, the FBI and a few other Democrats tried to overthrow the U.S. Government while Donald Trump was President.  The moment he got in office, they impeached him and they've impeached him again.  Worthless, ruthless, deceiving Democrats.  They totally ignored 75 million Americans who voted him into office.  Hillary couldn't stand to lose.  

Pelosi should be deported to China or Iran.

Too many spineless, gutless RepubliCONS are guilty along with him, and so deflect ..

Because you're lying again. 

Many in the GOP think thats OK.

No he didn't - he was the government. You may not have realised this, but challenges to elections in the US happen every time there is one

Because he has the support of corrupt republican senators who go along with his crimes.