Presidential candidates in the United States believe that the wealth of the United States is now unequal, and if heavy taxes are imposed, the gap between the rich and the poor in the United States can be alleviated and social welfare can be increased. However, this idea is just an idea after all. Many developed countries have mentioned this proposal, but few countries have succeeded so far. Because this tax law is difficult to implement.

Bernie sanders, a presidential candidate from Vermont, said that if he wins the election in 2020, he will raise nearly $4.5 trillion in ten years to realize three social welfare programs: universal health insurance, universal child care service and affordable housing. As for the source of this huge sum of money, the senator said that it was mainly through levying a "wealth tax" on the super-rich.

But this idea may face many challenges at present. First of all, we must have absolute right to speak in the Senate and the House of Representatives. Secondly, we must find legal support. American legal experts said that this proposal could not find any supporting provisions in the country's constitution, which was the biggest obstacle.

Of course, the United States is not the first country to have this idea. According to the data of the Tax Foundation, among the 36 developed countries in the world, 14 once levied wealth tax, but now this number has been reduced to only four. Because the implementation effect of this tax is not ideal, the rich can always find ways to evade taxes or win political immunity. "This can greatly reduce the wealth inequality in the United States and prevent our democracy from becoming a corrupt oligarch, so we must do this." Bernie sanders said.