Italian Premier Matteo Renzi's candidate in this week's presidential election could cost him backing for his reform agenda.

Lawmakers were voting in Parliament Friday, a day after a first round fell far short of producing the two-thirds majority needed to elect a new head of state. Chances of victory improve on Saturday, when only a simple majority is needed.

Renzi has urged his Democrats and coalition allies to vote for Sergio Mattarella, a constitutional court justice.

But the choice angered opposition leader Silvio Berlusconi's forces. Decades ago, Mattarella raised conflict-of-interest concerns after the media mogul jumped into politics.

The risk for Renzi is that Berlusconi might now renege on promises to back the premier on electoral reforms aimed at making governments more stable.