re: Why is Obama hell bent on amnesty for 10's of millions of illegals?

Why is is presumed that amnesty would create a larger Dem voting block? Hispanic culture tends to be very catholic and with that one could think that some of the social issues that are pushed by Dems would tend to sway the vote to the Republicans. Also would the addition of 10 million tax payers have an adverse affect on the economy? Presumably most are working at some job now just not paying income tax.