The long term
All that said, and even if there is quick shutdown effect in the polls, the midterm elections are not until November. With Trump in the White House, it’s difficult for any story to stay at the top of the news cycle for more than a few days. With that in mind, it’s easy to see one side picking up political support in the immediate aftermath of the shutdown, only for that bump to fade with time.
Indeed, prior shutdowns haven’t had long-term electoral implications. Republicans recovered on the generic ballot by February 1996, just a month after the final shutdown of that period ended. And in the elections later that year, they held onto their majorities in both the House and Senate. Clinton, meanwhile,
recovered his lost support by March 1996. He would go on to easily win reelection later in 1996.
Basically, America put the same people who shut the government down back in office.
The 2013 shutdown tells the same story. Despite losing the blame game, Republicans jumped to a lead on the generic ballot by late November 2013 — their first of the year. In the
2014 midterms, they expanded their majority in the House and won back the Senate. Meanwhile, Obama
continued a long-term decline in his approval ratings in the months following the 2013 shutdown, but recovered to his pre-shutdown approval level
by April 2014.