She will go up against Republican nominee Daniel Butierez to fill the US House seat her father held until his death earlier this year

Adelita Grijalva is the front-runner to replace her father in Congress but faces an unexpectedly competitive primary featuring a young social-media-savvy newcomer.

The next test of who Democratic voters want to see leading the party will take place Tuesday in southwest Arizona, where three leading candidates are offering competing visions in the primary to fill the late Rep.