Senate to hold procedural vote after Ukraine briefing descended into row over border crisis. If vote fails, negotiators will be back to square one

Ukrainian leader was due to address senators ahead of vote on emergency aid package, including more than $60bn in new military support

The bottom line will be this: Can anyone consolidate the anti-Trump vote and peel off enough support from the former president to compete with him?

Nikki Haley scored two big-money prestige endorsements last week that strikingly boost her standing in the Republican primaries. The Koch Brothers’ conservative money machine, Americans for Prosperity Action, lined up behind the former South Carolina governor, a move that could provide her with maximum financial support, especially if she overtakes, as she seems poised to do, Ron DeSantis as the designated Trump alternative. And then she captured the public favour of Jamie Dimon, the chief executive of JPMorgan Chase, a mega donor and major business voice.