Argentines are voting in nationwide congressional elections that mark the beginning of the end of a government led by Cristina Fernandez and her late husband Nestor Kirchner since 2003.

After a decade of increasing presidential power, new majorities in Congress could try to limit her ability to make unilateral decisions in the last two years of her second term.

Fernandez remains Argentina's most popular politician nationwide, and has dominated rivals by having allies float the idea of a "re-re-election" to a third term. But Sunday's vote was expected to bury that idea by denying her the votes in congress needed to change the constitution. That will make her a lame-duck president with no clear successor.