House GOP majority on the brink as all-Democrat Texas special congressional election underway

Republicans are clinging to a razor-thin 218-213 House majority.

And the GOP's margin will shrink even further after a special congressional election this weekend to fill the seat in a Democrat-dominated district which has been vacant for nearly a year.

That's because the two candidates in Saturday's runoff election in Texas' 18th Congressional District are both Democrats.

Voters in the district, which is anchored by downtown Houston and surrounding areas, head to the polls to...