HAHAHAHAHAHAHAHA!
So, even though most Muslims are peaceful, and the only ones who have contorted Sharia law happen to be a part of brutal regimes in countries such as Iran and Saudi Arabia, you are totally opposed to having Muslims dominate any part of Western governments?
Do you have any idea how xenophobic and downright ignorant that mentality is? The Muslim leaders you are referring to have raped and contorted Islam in the countries they govern. As Superman4ever pointed out, the reason why Sharia law is so brutal in these countries has to do with how governments have interpreted the laws over the past several centuries.
Western Muslims are RADICALLY different from the power-hungry dictators which dominate the Middle East. We have two Muslim Congressmen in the United States (
and there might be a third this November, s-c-a-r-y 
), and NEITHER of them have pushed for legislation which would enact Sharia law; in fact, Keith Ellison, the first Muslim Congressman to EVER serve in the House of Representatives, has gone on record to say that he opposes the interpretations of Sharia law which have had detrimental affects on several countries in the Middle East.
So, really, I do not understand why you CARE so much that the United States may see a rise in Muslims over the coming decades. There is NO WAY any radicals will slip into Congress; there is NO WAY Sharia Law will become the "law of the land"; there is NO WAY our society will crumble in the process. This country shouldn't fear Muslims, it is the sort of ignorance you have projected in your above post which makes me despise the post-9/11 mentality which exists among too many Westerners.
Heck, you want to know what makes me MORE afraid than possibly seeing an influx of Muslim politicians and leaders? The possibility that we'll see a Christofascist such as Mitt Romney or Bobby Jindal or Mike Huckabee become President, and they'll push to write discrimination into the Constitution in more ways than one. Because that is a LIKELY scenario, that a pretty, white Christian male will come into office sometime in the next decade and decimate our country's laws by projecting HIS views and HIS beliefs into every aspect of government, from bills to Constitutional amendments to Supreme Court appointments. That is a reality we have had to FEAR for years and years, and thankfully our Congress has been resistant enough to knock down many of the Christofascist efforts of George W. Bush over the past eight years.
Yeah... to me, Christianity and Islam are one in the same, in terms of hierarchy and viciousness. The difference between the two, however, is that Christianity has been serving as an oppressive religion in this country for way too long, and Islam will never become so prominent in my lifetime.
Open your eyes.