Rep. Val Demings, a former police chief, says 'painfully obvious' that Capitol police 'were not prepared'; Rep. Tim Ryan says people will be 'without employment very, very soon'

Presumptive Democratic candidate previously said he would reveal his running mate at the beginning of August; selection must be made before party convention opens on August 17

Key Republican senator opposes fresh testimony; defense attorney Dershowitz causes controversy by suggesting president is immune if he believes he acted in national interest