Direct democracy permits the majority to trounce the rights of the minority.
A better answer would be that candidates for public office could only accept campaign contributions from registered voters in the candidate's district. This would beholden the candidate to his voters.
The patriot act wasn't a result of direct democracy, but getting rid of it would be much easier under direct democracy. Government involves both the creation and ammendment/removal of statutes.
Direct democracy is no more likely to lead to tyranny of the majority than representational democracy (slavery and segregation was an act of representational democracy if you recall). You are confusing two dimensions: direct <--> representative with majoritarianism <--> constitutionalism. Direct democracy is perfectly compatible with all the checks and balances of liberalism and a constitution.