A national wealth tax has gone nowhere. Now some states want to tax the ultra-rich.

The idea of a national wealth tax has been floated for years by the likes of President Joe Biden and Senator Elizabeth Warren, although without yet gaining traction in Congress. Now, a group of lawmakers from eight states say they're stepping in to introduce their own wealth taxes, with the goal of raising billions to fund social programs. 

The lawmakers, who represent Democratic-leaning states including New York, Washington and California, say their new wealth taxes are necessary because the quirks of the federal tax code allow multimillionaires and billionaires to avoid paying their fair share.

The wealthiest 1% of Americans have seen their fortunes grow 19 times faster than the bottom half of the population during the last decade, according to a report released this week from anti-poverty charity Oxfam and other groups. One reason the rich are able to grow their wealth faster than others is partly due to differences in taxation, with capital gains — income from investments — taxed at a lower rate than earned income.