Sanders wealth tax is a tax on widows and widowers

See The Trophy Wife Tax Credit by Greg Mankiw. 

"As I have pointed out, Elizabeth Warren's wealth tax, as described, involves a substantial marriage penalty. Now Bernie Sanders comes along with his own wealth tax proposal. He solves the marriage penalty problem by halving the thresholds for singles.  This approach introduces the opposite problem--a marriage bonus.

As I understand the plan, if a single man is worth $30 million, he pays $140,000 per year under the Sanders wealth tax. If he marries his assistant, who has a wealth of less than $2 million, their tax liability falls to zero.

For a single man with higher wealth, the marriage bonus is even larger. Under the Sanders plan, for someone worth $100 million, marriage reduces the tax liability by $410,000 per year.

Put another way, this plan can be viewed as imposing a tax on widows and widowers. A married couple worth $30 million does not pay anything. When one spouse dies, the surviving spouse then owes $140,000 per year."