(CNN) Democrats have taken a tumble on the generic congressional ballot over the last few months. Their advantage in an average of the last five live interview polls is just under 7 percentage points, and it's even lower when you consider other polls.

The Democrats, though, have been taking solace in special election results since Donald Trump became President. In over 120 special congressional and state elections, they've been outperforming the partisan baseline based on the last two presidential elections by an average of 12 percentage points. A swing of greater than 7 points is generally consistent with Democrats taking over the House in November, though the exact break point is not knowable.

Special election results haven't been nearly as good for Democrats since the beginning of April, however.

In 25 special elections since April 1, Democrats have been outperforming the partisan baseline based on the last two presidential elections (or just the 2016 election in two Alabama special elections because of a lack of data) by an average of only 6 percentage points. The average is skewed by a few outliers. In the median special election since April 1, Democrats have been outperforming the partisan baseline by only about half a point.

In other words, Democrats aren't doing any better in special elections over the last two months than the generic congressional ballot would suggest that they should be doing. In fact, their overperformance in recent special elections has been about half as high as it had been in all special elections since January 2017.

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