David Bruce Vitter (born May 3, 1961) is an American lobbyist, lawyer and politician who served as United States Senator for Louisiana from 2005 to 2017. He was the first Republican elected to the Senate from his state since the Reconstruction Era. Previously, he served in the United States House of Representatives, representing the suburban Louisiana's 1st congressional district. He served as a member of the Louisiana House of Representatives before entering the U.S. House.

Vitter has been actively involved with legislation concerning illegal immigrants. In June 2007, he led a group of conservative Senators in blocking federal Immigration Legislation that would have granted a pathway to legal residence to 12 million illegal immigrants coupled with increased border enforcement. The bill's defeat won Vitter national attention as the bill was supported by President George W. Bush, John McCain, and Ted Kennedy, among others. Vitter characterized the bill as amnesty, which supporters denied. Bush accused the bill's opponents of fear mongering.  In October 2007, Vitter introduced an amendment withholding Community Oriented Policing Services funds from any sanctuary city which bans city employees and police officers from asking people about their immigration status in violation of the Illegal Immigration Act. Democratic Senator Dick Durbin, in opposition to the amendment, said these cities do not want to inquire about someone's status if they report a crime, are a victim of domestic violence or get vaccinations for their children. The amendment was defeated.  In November 2007, Vitter introduced a bill requiring banks to verify that no customer was an illegal immigrant before issuing banking or credit cards. The bill never made it out of committee.  In March 2008, Vitter reintroduced the latter two proposals and cosponsored ten of eleven other bills in a Republican package of tough immigration enforcement measures including jail time for illegal border crossing; deportation for any immigrant (legal or illegal) for a single driving while intoxicated; declaration of English as the official language (thereby terminating language assistance at voting booths and federal agencies)' additional construction of a border fence; permission for local and state police to enforce immigration laws and penalties for states who issue drivers licenses to illegals. None of these proposals passed, partially because the Democratic-controlled Senate preferred a comprehensive approach which would include a guest-worker program and a path to citizenship for the current population more akin to the package defeated by Vitter in 2007.  In April 2008, Vitter introduced a joint resolution proposing a constitutional amendment that a child born in the United States is not a citizen unless a parent is a citizen, lawful permanent resident, or alien serving in the military. Currently the Constitution grants citizenship to children born within the U.S. regardless of the legal status of the parents. The bill never made it out of the Democratic-led committee.

Using a quote from the above article, answer the following question: Whats the last thing he did immigration wise?
a constitutional amendment that a child born in the United States is not a citizen unless a parent is a citizen, lawful permanent resident, or alien serving in the military.