It was only a month ago that Republicans seemed to post substantial gains on the generic congressional ballot. They had pulled five percentage points behind Democrats by some measures after a Monmouth poll showed Democrats up by just two. That led to a wave of articles declaring that the Republican tax plan and strong economic growth had revitalized the party’s fortunes.

In February, it was hard to know whether the Republican surge would last.

A little over a month later, Democrats have recovered. The most recent Monmouth poll, published on Wednesday, gave Democrats a nine-point lead. Over all, Democrats lead the most recent generic ballot polls by around nine points, about the same as their standing before the tax debate began.