U.S. Presidents sometimes appointment members of the opposition party to cabinet positions (like Secretary roles). This is often done to bring in expertise. Here are a few examples:
Barrack Obama (Democrat) kept Republican Robert Gates as Secretary of Defense. He also appointed Ray LaHood (Republican) as Secretary of Transportation.
Joe Biden (Democrat) appointed Republican Lloyd Austin as Defense Secretary.
George W. Bush (Republican) appointed Democrat Norman Mineta as Secretary of Transportation.
Donald Trump (Republican) appointed James Mattis (Independent) as Defense Secretary.
Abraham Lincoln appointed several political rivals.
Franklin D. Roosevelt (Democrat) appointed Republican Henry L. Stimson as Secretary of War during World War 2.
Since many people in India want to follow many American practices, why don’t they follow the above and appoint Shashi Tharoor as External Affairs Minister or Indian Ambassador to the United Nations or United States.
At State level, appoint K. Annamalai as in-charge of Police in Tamil Nadu.
Appoint Palanivel Thiaga Rajan as Finance Minister of Tamil Nadu.
Will they do? I don’t think so.