Barack Obama made his name by telling us that there aren't two separate Americas, black and white, but just one United States. Still, knowing the color of a voter's skin offers a fair amount of information about how that voter feels about the president. Among white voters, it's been dropping since this spring. Joan Walsh discusses some of the likely reasons, and some of the possible inflection points, in her blog; here, we're simply going to look at the numbers, and then look at what was happening in the political world while those numbers were being collected. Using Gallup polling data, the following charts show how President Obama's approval rating broke down among white, nonwhite, black and Hispanic poll respondents, and how those figures changed as specific key events occurred.

Jan 20: Barack Obama is inaugurated as president.

Date	White	Nonwhite	Black	Hispanic
Jan 19-25	63	78	86	74
Jan 26-Feb 1	61	80	90	75
Feb 2-8	59	79	92	73
Feb 9-15	58	81	91	77

Feb 17: The president signs the stimulus package into law.

Feb 18: President Obama proposes his mortgage relief plan.

Feb 19: Rick Santelli delivers his rant on the trading floor of the Chicago Mercantile Exchange.

Date	White	Nonwhite	Black	Hispanic
Feb 16-22	56	78	91	76

 Feb 26: The White House releases its bold budget proposal.

Date	White	Nonwhite	Black	Hispanic
Feb 23-Mar 1	58	79	94	73
Mar 2-8	55	80	96	77
Mar 9-15	55	79	90	74
Mar 16-22	58	77	92	70
Mar 23-29	54	79	95	74
Mar 30-Apr 5	57	75	91	70
Apr 6-12	54	79	92	75

Apr 15: Protesters mark Tax Day by attending Tea Party events around the country.

Date	White	Nonwhite	Black	Hispanic
Apr 13-19	55	82	94	79
Apr 20-26	57	85	96	85
Apr 27-May 3	58	84	92	84
May 4-10	58	84	92	84
May 11-17	56	83	91	85
May 18-24	57	82	91	78

May 26: Obama nominates Sonia Sotomayor for the Supreme Court.

May 27: Sotomayor's "wise Latina" comments emerge.

May 27: Newt Gingrich attacks Sotomayor as "racist."

May 28: The president calls criticisms of Sotomayor "nonsense," but adds, "I'm sure she would have restated it."

Date	White	Nonwhite	Black	Hispanic
May 25-31	56	81	90	79

June 2: Sen. Pat Leahy, chairman of the Judiciary Committee, calls attacks on Sotomayor "unbelievable" and "vicious."

June 4: The president delivers his speech to the Muslim world in Cairo.

Date	White	Nonwhite	Black	Hispanic
June 1-7	55	83	95	82
June 8-14	54	79	94	75
June 15-21	54	79	94	75
June 22-28	52	83	94	81

July 1: Unemployment reaches 9.5 percent.

Date	White	Nonwhite	Black	Hispanic
June 29-July 5	52	82	96	81
July 6-12	51	78	91	75

July 13: The Senate Judiciary Committee begins confirmation hearings for Sonia Sotomayor.

July 15: Sen. Tom Coburn tells Judge Sotomayor, "You've got some 'splainin' to do."

Date	White	Nonwhite	Black	Hispanic
July 13-19	51	81	94	79

July 20: The first notable disruption of a congressional home district meeting occurs, when a Birther hijacks Delaware Rep. Mike Castle's attempt to discuss healthcare with constituents.

July 20: The arrest of Henry Louis Gates, Jr. at his Cambridge, Mass. home becomes public.

July 21: The president comments on the arrest in a press conference, saying the police acted "stupidly" in arresting Gates.

July 22: Liz Cheney attempts to justify Birtherism on CNN, saying, "People are uncomfortable with a president who is reluctant to defend the nation overseas."

July 24: Obama says of his comments on the Gates arrest, "I could've calibrated those words differently."

Date	White	Nonwhite	Black	Hispanic
July 20-26	47	79	95	72

July 28: Birther frenzy reaches an approximate peak.

July 28: The Senate Judiciary Committee votes to confirm Sonia Sotomayor.

July 29: Obama redoubles his healthcare sales pitch, holding public meetings in Raleigh, N.C., and Bristol, Va.

July 30: Professor Henry Louis Gates Jr. and Sgt. Joseph Crowley go to the White House for a beer with the president and vice president.

Date	White	Nonwhite	Black	Hispanic
July 27-Aug 2	46	76	94	68

Aug 3: Members of Congress on recess find hostile, combative crowds at town halls.

Aug 6: The full Senate votes to confirm Sonia Sotomayor.

Aug 7: Sarah Palin worries, in public, about "death panel" measures in the healthcare reform proposals.

Date	White	Nonwhite	Black	Hispanic
Aug 3-9	47	79	96	77

Aug 11: William Kostric brings his 9 mm pistol to the president's town hall meeting in Portsmouth, N.H. He carries a sign saying, "It is time to water the tree of liberty" and seems to touch off a trend of bearing arms to town halls.

Date	White	Nonwhite	Black	Hispanic
Aug 10-16	46	73	92	69

Aug 22: Obama denounces "outrageous myths" about healthcare reform.

Date	White	Nonwhite	Black	Hispanic
Aug 17-23	45	72	91	67
Aug 24-30	43	71	86	67
Aug 31-Sept 6	45	74	91	68