In a closely-watched race, Arizona voters on Tuesday will choose a candidate to complete the remainder of Rep. Gabrielle Giffords’s term in Congress nearly 18 months after a gunshot wound to the head, which forced her to resign in January.

The names on the ballot will be Ron Barber as the Democrat and Jesse Kelly as the Republican. But perhaps the two more important names in the race are those of Giffords and President Obama – the former still invoking significant goodwill here, the latter far less so.