Last Monday, Gallup’s national 5-day polling (taken from January 11-15) showed Mitt Romney leading his nearest competitors in the Republican presidential field (Newt Gingrich and Rick Santorum) by a colossal 23 percentage points — 37 to 14 percent. Just seven days later, Romney’s lead over Gingrich is now down to 1 point — 29 to 28 percent — as Gingrich’s support has doubled and Romney’s has dropped by almost double-digits. The bulk of Gallup’s most recent polling (taken from January 18-22) was conducted prior to Gingrich’s win in South Carolina on the 21st.

Gallup shows Santorum down 3 percentage points (from 14 to 11 percent) between the two polls and Ron Paul up 1 point (from 12 to 13 percent).  Rick Perry had 5 percent support in last week’s poll but has since dropped out and endorsed Gingrich.