So its like Syria. Its not a civil war at all. Its part of the larger regional conflict between the US and its allies and its enemies such as Iran and Russia.
The larger regional conflict is attached to the regional conflict. The issues Houthis or Syrian Sunni majority had before the war did not come from outside.
"The Bush Administration has been quietly nurturing individuals and parties opposed to the Syrian government in an effort to undermine the regime of President Bashar Assad."
The cable of the US ambassador in Syria, December 2006 via Wikileaks: