She was a member of the liberal wing of the Socialist Party, close to Jean-Marie Bockel, but she joined Bockel's Modern Left (LGM). The Modern Left is a member of the presidential majority of Nicolas Sarkozy. Striffler is assistant to the mayor of Mulhouse, Bockel.
In the 2009 European elections, she was the second candidate on the Union for a Popular Movement (UMP) list in the East region, and was elected to the European Parliament, where she sat with the Group of the European People's Party.
At the 2014 European election, she was third-placed on the UMP's list in the East constituency. Her party won only one seat in the region, so she was not re-elected.