An illustrative example of a policy area where a more cohesive approach is needed is income inequality, a concern virtually all Democrats share. Reading the coverage of the presidential primary, you could be forgiven for thinking my fellow Democrats have to choose between two stark alternatives: a wealth tax on one hand and supporting the status quo on the other.

I believe there is more potential for common ground — and intellectually honest give-and-take — than the drama of the primary suggests. Finding this common ground, however, will require both sides to make concessions. For the party’s more moderate factions, that starts with recognizing that the measures Democratic presidents have been able to achieve to address income inequality have fallen short. The gap between the wealthiest 0.1 percent of Americans and the other 99.9 percent is greater than ever. To close great and growing wealth and income gaps, and to raise badly needed revenue for public investment, it’s not enough to lift the bottom up; we need to ask more of those at the top, too.

Moderate members of the Democratic Party must recognize the popular resonance of a wealth tax, even if, like me, they don’t support it. Roughly 74 percent of American voters, including a majority of Republicans, support a 2 percent wealth tax on those worth more than $50 million. When I served in government, Americans were wary of taxing the very wealthy, but public opinion — and the politics of taxation — has changed. A wealth tax is on the table.

But it shouldn’t be the only option on the table. Just because the wealth tax is good politics doesn’t necessarily make it good policy. A plan to bring the top down and reduce inequality must be constitutional and administrable. There are strong reasons to believe a wealth tax is neither. A wealth tax is likely to be struck down by the Supreme Court as a direct tax not apportioned among states, as the Constitution requires. And even if it survives a legal challenge, valuation is likely to prove prohibitively challenging, and taxing illiquid assets presents serious problems.

Even those who strongly support a wealth tax must concede that other plans exist and that they ought to be part of the debate. Economists have put forward revenue-raising proposals that reduce inequality, such as raising corporate, capital gains and personal income tax rates; broadening the tax base; converting deductions to more limited credits; strengthening the estate tax (including by eliminating stepped-up basis, a tax code provision that allows heirs to minimize estate taxes); and imposing a financial transactions tax, as recently proposed by Mike Bloomberg and supported by many leading progressives.