- - Tuesday, April 22, 2014

President Obama’s declining popularity and his supporters’ potentially low turnout threaten to squeeze Democrats this November.

On one side is the current danger from the president’s declining support among independents, and even some Democrats. On the other is a possible repeat of the reduced Democratic participation that occurred in 2010. Together, these phenomena could act like a vise to put serious political pressure on Congressional Democrats.

A continued weak economy and Obamacare’s implementation have had a decidedly adverse effect on Mr. Obama’s standing with voters. Earlier this month, a Quinnipiac University nationwide poll of 1,578 registered voters showed how serious the erosion has been in his public support.

The president’s overall job rating was 42 percent approval to 50 percent disapproval, and he was rated negatively by every age group. Forty-two percent is just slightly better than Quinnipiac’s all-time low for Mr. Obama of 38 percent from December of last year.

Looking inside these numbers, the results are worse. To reach 42 percent, Mr. Obama had to garner a very high 79 percent approval rating from Democrats. This was needed to offset extremely low ratings from independents (37 percent approval vs. 52 percent disapproval) and abysmal Republican ratings (4 percent vs. 93 percent).

Just how much a deterioration this is can be seen by comparing these figures with exit polling from Mr. Obama’s 2012 re-election. Just two years ago, 92 percent of Democrats and 45 percent of independents voted for the president.

These figures show Mr. Obama is now completely dependent on overwhelming Democratic support to reduce his losses among the rest of the electorate. Yet even among Democrats, the president’s support has fallen.

The problem for congressional Democrats is even worse than it is for the president. They face voters in this November’s midterm election. In the previous midterm, Democratic voters were a much smaller portion of the electorate than they had been with Mr. Obama on the ballot in 2008.

In 2010, Democrats fell to 35 percent of voters, compared to 40 percent in 2008. In contrast, Republicans increased from 33 percent to 35 percent, and independents rose from 28 percent to 29 percent.

For congressional Democrats, the story looks like this: Where Mr. Obama’s support is the strongest, turnout fell; where Mr. Obama’s opposition was greatest, turnout increased. Under the best of circumstances, this is the worst of outcomes. Yet currently, 2014 is offering congressional Democrats far from the best of circumstances.

Today, Republican and independent opposition to the president are about where they stood in 2010. Four years ago, 37 percent of independents voted for Democratic candidates. This is identical to the 37 percent approval rating independent voters give to Mr. Obama today. In 2010, 94 percent of Republicans voted for Republican candidates. This, too, is extremely close to the 93 percent disapproval rating Republicans give the president now.

However, despite still giving Mr. Obama overwhelming 79 percent support, Democratic voters are decidedly below the 91 percent rate at which they voted for Democratic candidates in 2010.

We can approximate electoral impact by multiplying party supporters’ electoral-participation rate by their approval rate for the party. Then we see that Democratic voters’ reduced support for Mr. Obama equates to a 4 percent drop for Democratic candidates — even if their participation level matches that of 2010.

So the vise grows even tighter for congressional Democrats. Not only is Mr. Obama’s overall support lower, his support is shrinking even among his most loyal supporters. Those supporters — in contrast to his opponents — are likely to see the greatest drop-off in turnout this November.

Much of this combined threat to congressional Democrats is below the surface of current national polling.

For one thing, polling does not pick up the threat of low turnout six months from now. It is far easier to respond favorably to a pollster’s question today than it will be to go to the polls in November. For another thing, heavy Democratic majorities in one area of the country can help offset negative responses in areas critical of the president.

While positive nationwide poll responses can help offset Mr. Obama’s declining national approval numbers, it cannot help congressional Democrats running in purple and red states this November, where large Democratic majorities do not exist to offset strong independent and Republican opposition to Mr. Obama.

Independent and Republican voters are already matching their dissatisfaction with the president in November 2010. In contrast, Democrats are lagging in their support for him. If those trends hold and the reduced Democratic voter turnout from 2010 is repeated, congressional Democrats will find themselves in a heck of a bind come November — one that could be worse than four years ago.

J.T. Young served in the Treasury Department and the Office of Management and Budget from 2001 to 2004 and as a congressional staff member from 1987 to 2000.