It is good that an American politician is speaking frankly about the nature of Islam and Islamic jihad. But  Tancredo is, like Robert Spencer, Lawrence Auster and countless others, misinformed about the nature of the Sharia "courts" in the UK.  "Britain's capitulation to Sharia" is a good soundbite, and the facts must never be allowed to get in the way of one of those. To quote from John Sullivan's piece.

Under British law, any two people can agree to take their dispute to such a tribunal rather than to court; the tribunal's decision is then binding on them. It can even be enforced by the official courts and the police.

[...]

Yes, arbitration tribunals can settle some disputes and have their judgments enforced. But they must act within the principles of English law: They can't forbid girls to attend mixed classes in school or award sons the bulk of inheritances merely because the parties agreed in advance to accept the verdict - any more than a regular court can enforce a voluntary contract of slavery or prostitution.

The Arbitration Act came into force in 1996, but arbitration, or "alternative dispute resolution"  has been around for several hundred years. From the legal point of view, absolutely nothing has changed. So if Britain has, as Spencer puts it (a little too eagerly) "capitulated" to Sharia, it has also "capitulated" to the laws of the Jedi Knight, or the Freemasons or of any other parties who agree to settle their disputes out of court.

Sullivan goes on to say:

Unfortunately, that is far from settling the matter. The police have reportedly been enforcing the sharia court's questionable judgments even though they lack legal force - for example, they've stopped questioning women who've accused their husbands of domestic violence once the tribunal has "settled" the case.

In fact the women withdrew their complaint. The police cannot investigate a complaint of domestic violence - whether involving Muslims or not - once the victim has withdrawn her complaint. So it is not that the case was "settled" by Sharia, or that what is against the law has suddenly become legal.

It is, of course, morally repugnant that the women were "persuaded" by the Sharia decision not to exercise their to justice under our laws. As I argue here, in fact the practical and non-legal dangers of Muslims becoming emboldened, are worse than anything these courts can do. What is legal may still be unjust, and these courts must be actively opposed.

Coming back to Tancredo, he is determined not to let America go the way of us tea-sipping pansy-asses. But it is quite possible that Sharia "courts" with exactly the same powers, or lack of them, already exist in the US. Does the US allow arbitration, where a decision may be legally binding if it does not go against the law of the land? If so, is Sharia specifically forbidden from being used in such arbitration? If yes to the first and no to the second, the US already has exactly what we have. Perhaps at the moment Muslims conduct these "courts" in secret; Muslims are not as arrogant in the US as they are over here. But what has happened in the UK can happen in any country that allows alternative dispute resolution and does not explicitly forbid Sharia in that context. Someone should go undercover in Dearborn, Michigan and see what he finds there.

Tancredo is right to propose barring entry to Muslims who advocate Sharia law, and to make this a deportable offence. What is not clear is how you can be a Muslim and not wish for Sharia law. Realistically you would need to bar entry to all Muslims and deport all Muslims. While the former is feasible, the latter is unlikely to happen.