Final version :^)

#!/usr/bin/env python
import mechanize, time, re
import random, string
def genname():
    length = random.randint(3, 12)
    s = ''
    while len(s) < length:
        s += random.choice(string.lowercase)
    return s
def signit():
    print 'Starting'
    url = 'https://www.hillaryclinton.com/forms/rnc-open-letter/'
    name = genname()
    name2 = genname()
    email = genname()+'@gmail.com'
    postalcode = str(random.randint(10000,50000))
    print 'Signing as %s %s / %s (%s)' % (name, name2, email, postalcode)
    br=mechanize.Browser()
    br.set_handle_robots(False)
    br.open(url)
    print 'Connected'
    br.form = list(br.forms())[0]
    br.form['givenName'] = name
    br.form['familyName'] = name2
    br.form['email'] = email
    br.form['postalCode'] = postalcode
    br.submit()
    print '********Success********'
while True:
    signit()