Trump supports getting rid of the alternative minimum tax. Now we know why.

AP

On Tuesday, MSNBC revealed part of President Donald Trump's 2005 tax returns, which showed that Trump paid $38 million on $150 million worth of income that year. 

The majority of that bill — $31 million — is based on the alternative minimum tax, which is designed to make rich people pay their fair share. 

It also just happens to be one of the many taxes Trump wants to abolish. Trump's tax plan from his 2016 presidential campaign called for the elimination of the alternative minimum tax as well as a reduction of federal income tax rates overall.

Trump's federal tax bill after deductions was $5.3 million or just under 4% of Trump's income, according to the Daily Beast. Because of the alternative minimum tax, Trump was forced to pay an additional $31 million, bringing his tax bill up to 25.33% of his income.

The alternative minimum tax was established nearly half a century ago to make sure wealthy people could not eliminate significant portions of their tax bill using deductions.