Bavaria's former premier, Edmund Stoiber, has said the CSU is a victim of its own success after the party fell to a new low in the polls. Sunday's vote in Bavaria will likely see the CSU lose its parliamentary majority.
Specifically, migration to Bavaria from the rest of Germany was the main threat facing the conservative CSU's parliamentary majority in Sunday's regional election, Stoiber told the German media group Redaktionsnetzwerk Deutschland.
"In recent years, our economic success has seen a one-way migratory flow coming into Bavaria," said Stoiber, the CSU's honorary chairman, on Wednesday.
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"More than 1 million people have come to us from all parts of Germany in the last 10 years," he said. "Bavaria is top of the league in Germany. However, greater economic prosperity can also spur other reactions."
The most recent polls see the CSU taking just 33 percent in Sunday's vote. Such an outcome would mark a huge disappointment for a party that has historically governed alone in its native state thanks to a typical vote share of around 50 percent.
If the CSU wants to govern with just one junior coalition party, forecasts have suggested it would have to forge an agreement with either the environmentalist Greens or the far-right Alternative for Germany (AfD), who are slated to take 18 and 14 percent of the vote respectively, according to polls.
"I don't see how a stable alliance could be possible with these differences [between the CSU and Greens]," Stoiber said Wednesday.
Otherwise, the CSU would need to forge a three-way coalition, most likely with the business-friendly Free Democrats (FDP) and one of either the Social Democrats (SPD) or the centrist Free Voters of Bavaria.