Since the Kohl era ended two years ago, German politics has been extremely volatile as the main parties have fought for the center ground. But all is not necessarily well in the coalition. The Greens are becoming tired of the straightjacket imposed upon them by their senior partners. It has also become easier for the CDU opposition to score more meaningful points.
Immigration is one of the obvious issues here.
If it can avoid appearing xenophobic, the CDU could win a lot of votes with a policy of stricter controls.