The special election in Pennsylvania is the latest sign that Republicans may lose a lot of seats this fall. But they are finding it hard to do much about their problems.
Problem number one is that Donald Trump is not popular in the country as a whole, and he is especially unpopular in middle-class suburbs. His erratic behavior and growing list of scandals won't help. But he remains wildly popular with the Republican base, which makes it all but impossible for any Republican to run away from the president. So Republicans are stuck with this albatross.
Problem number two is that during the campaign Trump positioned himself as a moderate on a range of economic issues, promising to preserve Social Security and Medicare, to be tougher on big banks than Hillary would be, and so on. This seems to have helped him win. But Republican Congressional leaders are strongly conservative on all these issues, and so far they have been driving the agenda. Their plans are not popular with swing voters; Obamacare has gotten a lot more popular since Obama left office, and Social Security reform has always polled horribly. But they are the main thing, pretty much the only thing, to the party's donors and much of its intellectual leadership, making them impossible to abandon. So the Republicans are going into this election with both an unpopular leader and an unpopular economic agenda.
Of course the Democratics have big problems of their own, so I don't see a Democratic wave as a given. But it looks more and more likely.