Congress has handed away its constitutional authority to the White House, a shift that weakens the checks meant to limit any president's power.

• The Constitution set up three co-equal branches, but the legislative branch no longer acts like one.
• Lawmakers now back whichever president shares their party instead of pushing back on him.
• Republicans in Congress defend a Republican president; Democrats do the same for a Democratic one.
• Oversight committees have stopped overseeing and mostly cheer the White House on.

Outlook: Without lawmakers willing to challenge their own party's president, executive power keeps growing.