They would like to impose compulsory Shariah law upon everyone but currently that is highly unrealistic so in the meantime every time one hears about Shariah laws in the West it's the "optional and for Muslims" kind. In a future where conservative Muslims have become the majority in terms of percentage of the population the "compulsory Shariah for all" scenario will become possible. In some countries here in Europe they could possibly become the majority within this century, in the US it would take hundreds of years.