Kamala Harris was due to deliver a tough-on-illegal-migration message after visiting the US-Mexico border Friday, directly tackling the politically explosive issue in a bid to blunt one of Donald Trump's main attack lines in their fight for the White House.
The US vice president's trip to Arizona -- her first to the border since replacing President Joe Biden as Democratic nominee in July -- comes as polls show illegal migration remains one of her biggest vulnerabilities against the Republican.
