Bonds were moderately stronger in the overnight session thanks to European political uncertainty, among other things.  One of those "other things" could simply be the fact that Friday afternoon's weakness was a bit overdone simply because it occurred on a Friday afternoon (traders not wanting to be over-exposed heading into a weekend with or without European political uncertainty).  

Domestic markets really started moving when doubts were cast as to the viability of the Trump's tariff announcement.  Sorry about the passive voice there... To be specific, newswires cited Republican leaders as urging Trump not to advance on the planned tariffs.  Other sources said the GOP wouldn't rule out "potential action" if Trump doesn't back down.  Trump subsequently said he wasn't backing down.

The endgame of the brinksmanship is unclear, but the net effect was the casting of doubt on the tariff plan.  Those doubts helped stocks recover much of their post-Tariff-Announcement weakness from last Thursday.  Unfortunately, bonds experienced the tariff move as a positive event last week, so reversing course meant heading back toward higher rates.

A gigantic, looming corporate bond from CVS applied general pressure to today's weakness.  We knew this deal was coming this week, but today's chatter suggests it will arrive tomorrow and be another $4 billion bigger than initial estimates ($44 bln in total--one of the biggest ever).  Corporate bond issuance tends to push rates higher for reasons discussed in this primer.