Washington Senator Patty Murray has introduced the Retirement and Income Security Enhancements – or “RAISE” – ACT, which would increase Social Security benefits for single women and children, financed by a new tax on high earners. Some of the RAISE Act’s provisions make sense. But the plan itself is a bad idea, for one simple reason: it would effectively tap out high earners for additional taxes but does next to nothing to fix the program’s multi-trillion funding shortfall. If the RAISE Act is passed, it’s more likely that fixing Social Security’s solvency will involve substantial benefit cuts for all.

The RAISE Act has four main elements. First, it would allow divorced individuals to receive benefits based on the former spouse’s earnings after only 5 years of marriage, versus the 10 years requirement under current law. Second, it would make Social Security survivors’ benefits equal 75 percent of the former couple’s total benefit, rather than 50-66 percent as under current law. Third, it would allow children of deceased or disabled workers to collect benefits through age 23, rather the current age of 18.

And finally, it would apply a 4-percent surtax on earnings above $400,000. In exchange, individuals paying this higher tax would receive a nominal increase in their benefits.

The RAISE Act’s benefit increases aren’t unreasonable. While they lack an obvious rationale – it’s not clear why a divorced individual should receive a lifetime of benefits after only 5 years of marriage, or why a 23-year old should continue to be paid benefits as a child – they’re targeted on needy individuals and some have even been proposed by Republicans.

The RAISE Act’s tax increase obviously comes with an economic cost. Under President Obama and Congressional Democrats, top tax rates have already risen significantly: from a combined income and Medicare tax of 38 percent when President Obama took office to 45 percent today. Add another 4 percentage points and the top federal rate hits 49 percent. While Washington has no income tax, in states such as California or Oregon a high earner pays 60 percent of each additional dollar to the government. That’s a higher top rate than in Sweden, Denmark, France or any other European country except for Portugal and Slovenia. And there’s a reason: top tax rates do reduce incentives to work and increase incentives to use tax shelters or flat out evade taxes.

But I understand not everyone accepts those arguments. So here’s a more practical one: there are only so many tax increases to go around. If you raise taxes to expand Social Security benefits for select groups, it’s more likely the system’s funding shortfall will be addressed by cutting benefits. Merely passing the RAISE Act’s tax increase would be politically difficult. To pass that tax hike and other tax increases to keep Social Security solvent is almost unimaginable. It’s just not going to happen.

According to the Social Security Administration’s actuaries, the RAISE Act increases tax revenues by $286 billion over its first 10 years and $1.2 trillion over 75 years, enough to solve around 12 percent of the system’s 75-year shortfall. That should give a picture of how large the Social Security solvency gap really is. But since the RAISE Act spends two-thirds of that extra revenue on expanding benefits, it reduces Social Security’s $10 trillion funding shortfall by only 3.6 percent and adds only one year to Social Security’s solvency.

Unless Senator Murray thinks she can pass tax increases large enough to fill the other 94 percent of the Social Security shortfall, it’s likely that the rest will be filled by cutting benefits. By using up tax hikes that might form the basis of a bipartisan compromise, the RAISE Act makes it more likely that all beneficiaries will be hit with a 25 percent benefit cut when Social Security’s trust fund runs dry in 2034.

The stereotype of Congress is that it thinks short-term, as in between now and the next election. The RAISE Act, with its targeted benefit increases for single women, whose votes skew heavily Democratic, doesn’t exactly disprove that allegation. Worse, Congress is accused of wanting to add new entitlements before it figures out how to pay for the ones it has. The RAISE Act fits that stereotype to a tee.

Sure, the RAISE Act would help some people, but what does Sens. Murray propose we do to make Social Security solvent for everyone?