Troop surge
Plan announcement: In a nationally televised address on January 10, Bush stated "America will change our strategy to help the Iraqis carry out their campaign to put down sectarian violence and bring security to the people of Baghdad. This will require increasing American force levels. So I've committed more than 20,000 additional American troops to Iraq. The vast majority of them – five brigades – will be deployed to Baghdad".
On the same day of the speech, ABC News announced that ninety advance troops from the 82nd Airborne Division had already arrived in Baghdad.

2007 State of the Union address: In advance of the State of the Union address, Bush gave several promotional speeches to Belo television and Sinclair television, suggesting that the surge "should be given a chance" and challenged critical lawmakers to offer an alternative.
On the night of Tuesday, January 23, the president had this to say on the troop increase in Iraq, outlining its purpose in supporting the Iraqi government's maintenance of control:

In order to make progress toward this goal, the Iraqi government must stop the sectarian violence in its capital. But the Iraqis are not yet ready to do this on their own. So we're deploying reinforcements of more than 20,000 additional soldiers and Marines to Iraq. The vast majority will go to Baghdad, where they will help Iraqi forces to clear and secure neighborhoods, and serve as advisers embedded in Iraqi Army units. With Iraqis in the lead, our forces will help secure the city by chasing down the terrorists, insurgents, and the roaming death squads. And in Anbar Province, where al Qaeda terrorists have gathered and local forces have begun showing a willingness to fight them, we're sending an additional 4,000 United States Marines, with orders to find the terrorists and clear them out. (Applause.) We didn't drive al Qaeda out of their safe haven in Afghanistan only to let them set up a new safe haven in a free Iraq.

Response: The substance of the debate that followed the speech reflected "widespread disagreement with the Bush administration over its proposed solution, and growing skepticism that the United States made the right decision in going to war in the first place". Some issues of contention were divisions over the advisability of committing more troops versus complete withdrawal, the 'winnability' of the Iraq War regardless of a surge, and framing of the issue.

Supporters: The New York Times reported that former Massachusetts Governor Mitt Romney and former New York City Mayor Rudolph Giuliani backed Bush on the troop increase. McCain did the same, saying on January 12 that "The presence of additional coalition forces would allow the Iraqi government to do what it cannot accomplish today on its own: impose its rule throughout the country."

Opponents: Immediately following Bush's January 10 speech announcing the plan, Democratic politicians, including Ted Kennedy, Harry Reid and Dennis Kucinich, called on Congress to reject the surge. Senator Dick Durbin issued the Democratic response which called upon Iraqis to "disband the militias and death squads." On January 18, Xinhua News Agency reported that "whitehouse hopefuls" Sens. Hillary Clinton, D-N.Y., Barack Obama, D-Ill., Chris Dodd, D-Conn., Joe Biden, D-Del, and Sam Brownback, R-Kansas, all voiced their discontent January 13 with the course of events in Iraq.
On January 17, Moveon.org released an ad that identified the surge strategy as "McCain's idea". The New York Times reported that presidential candidate John Edwards had "taken to referring to the administration proposal as 'the McCain Doctrine.'"
On January 18, the Los Angeles Times released a Bloomberg poll that said 60 percent of those polled opposed the troop surge, 51 percent wanted Congress to try to block Bush from sending more soldiers, and 65 percent disapproved of the president's handling of the war. Meanwhile, a Fox News Poll reported that 59 percent to 36 percent, Americans opposed sending more US troops to Iraq.

Congress: On January 16, Nebraska Republican Chuck Hagel, Delaware Democrat Joe Biden (Senate Foreign Relations Committee chair), and Michigan Democrat Carl Levin (Armed Services Committee chair) co-sponsored a non-binding resolution that said it was "not in the national interest of the United States to deepen its military involvement in Iraq."
House Speaker Nancy Pelosi said Democrats in her chamber would back a non-binding resolution "declaring that President Bush's decision to send additional troops to Iraq is 'not in the national interest of the United States.'" The Washington Times reported Pelosi "has made clear her disdain for the 'surge' proposal" since before Bush unveiled it last week, but her latest remarks "were her first indication of the language that she will want the House to approve."
After three days of debate, on February 16, 2007, the House of Representatives passed House Concurrent Resolution (HCR) 63 on a vote of 246 to 182.  The resolution stated:

Congress and the American people will continue to support and protect the members of the United States Armed Forces who are serving or who have served bravely and honorably in Iraq; and
Congress disapproves of the decision of President George W. Bush announced on January 10, 2007, to deploy more than 20,000 additional United States combat troops to Iraq.
Following passage in the House, Senate Majority Leader Harry Reid (D-NV) convened an unusual Saturday session of the Senate on February 17, 2007, to consider an identically worded resolution. However, the measure was tabled when a cloture motion failed on a 56–34 vote (four votes short of the 60 votes needed to end debate).
Pelosi announced that despite opposition to the surge, she would not push for blocking congressional funding for additional troops.

Implementation: 

Personnel changes: In conjunction with the surge, the Bush administration implemented several personnel changes, as follows:

CENTCOM commander– Navy Admiral William J. Fallon replaced General John Abizaid as CENTCOM commander
 Commander of Multinational Force Iraq – counter-insurgency expert General David Petraeus replaced General George Casey as Commander of Multinational Force Iraq.[3] Archived July 8, 2007, at the Wayback Machine
US Ambassador to Iraq and ambassador to the United Nations – Bush announced the appointment of US diplomat Ryan C. Crocker as the new ambassador to Iraq. Zalmay Khalilzad, then US ambassador to Iraq, was nominated to replace Alejandro Daniel Wolff as the US Ambassador to the United Nations. Khalilzad was confirmed by the Senate, he was the first Muslim to serve in the position, and he was the highest serving Muslim-American official in the US government.
US National Intelligence Director– John Negroponte resigned and became Deputy Secretary of State. Retired Admiral John M. McConnell took his place.
White House Counsel–  Harriet Miers stepped down.  She was replaced by Fred Fielding.

Units deployed: The six US Army brigades committed to Iraq as part of the surge were

2nd Brigade, 82nd Airborne Division (Infantry): 3,447 troops. Deployed to Baghdad, January 2007
4th Brigade, 1st Infantry Division (Infantry): 3,447 troops. Deployed to Baghdad, February 2007
3rd Brigade, 3rd Infantry Division (Heavy): 3,784 troops. Deployed to southern Baghdad Belts, March 2007
4th Brigade, 2nd Infantry Division (Stryker): 3,921 troops. Deployed to Diyala Governorate, April 2007
2nd Brigade, 3rd Infantry Division (Heavy): 3,784 troops. Deployed to the southeast of Baghdad, May 2007
1st Brigade, 10th Mountain Division (Light), September 2007 Deployed to Kirkuk
This brought the number of US brigades in Iraq from 15 to 20. Additionally, 4,000 Marines in Al Anbar had their 7-month tour extended. These included Marines from the 15th Marine Expeditionary Unit, 31st Marine Expeditionary Unit, the 2nd Battalion 4th Marines, the 1st Battalion 6th Marines and the 3rd Battalion, 4th Marines. Most of the 150,000 Army personnel had their 12-month tours extended as well. By July, 2007, the percentage of the mobilized Army deployed to Iraq and Afghanistan was almost 30%; the percentage of the mobilized Marine Corps deployed to Iraq and Afghanistan was 13.5%.

Operations: The plan began with a major operation to secure Baghdad, codenamed Operation Fardh al-Qanoon (Operation Imposing Law), which was launched in February 2007. However, only in mid-June 2007, with the full deployment of the 28,000 additional US troops, could major counter-insurgency efforts get fully under way. Operation Phantom Thunder was launched throughout Iraq on June 16, with a number of subordinate operations targeting insurgents in Diyala and Al Anbar Governorates and the southern Baghdad Belts. The additional surge troops also participated in Operation Phantom Strike and Operation Phantom Phoenix, named after the III "Phantom" Corps which was the major US unit in Iraq throughout 2007.

Counterinsurgency strategy: Counterinsurgency strategy in Iraq changed significantly under the command of General Petraeus since the 2007 troop surge began. The newer approach attempted to win the hearts and minds of the Iraqi people through building relationships, preventing civilian casualties and compromising with and even hiring some former enemies.