The White House announced Tuesday that it is seeking $500 million in supplemental border security funds and is sending 1,200 national guardsmen to the Mexico border.

The move came just as Sen. John McCain went to the Senate floor to call for a similar plan.

The two proposals have several key differences: The Arizona Republican’s would come in the form of an amendment to the supplemental war spending bill; it calls for an additional 6,000 troops to the border and $250 million in new spending.

GOP sources said Obama did not mention his border plan during his meeting with Republican Senators earlier Tuesday. However, Obama did use the session to call for Republican support for comprehensive immigration reform.

In his floor speech, McCain, who is facing a primary challenge from conservative former Rep. J.D. Hayworth, criticized Obama’s proposal. “It’s simply not enough,” McCain said. He also accused the White House of misrepresenting Arizona’s controversial new immigration law.

“It has been badly mischaracterized by administration officials who have admitted that they haven’t even read the bill,” said McCain, lashing out at “the liberal media and the mainstream media who have talked about our situation in Arizona. Most of them have never been within 100 miles of the border.”

McCain also harshly criticized Sen. Bob Menendez, who was on the floor at the time and objected to taking up McCain’s amendment immediately. While the New Jersey Democrat, also chairman of the Democratic Senatorial Campaign Committee, claimed his opposition was solely based on the fact that he hasn’t read the amendment, McCain accused him of seeking to obstruct his plan.

“I have been around here a long time. It’s the first time I have seen that from the Senator from New Jersey. And if that is the way we’re going to do business around here, then this place is going to grind to a halt. I think it’s discourteous of the Senator from New Jersey to do that. This place exists and runs on comity. I hope that is not becoming a practice around here or it will be practiced on this side” of the aisle also, McCain said.

Obama’s proposal is already resonating with Arizona Democrats who have been calling for National Guard deployments to their state’s southern border for weeks.

“The fulfillment of my request is a clear sign that this administration is beginning to take border security seriously,” said Rep. Gabrielle Giffords, who has been pressuring Obama to send in more troops since March 27, when a prominent Arizona rancher was murdered along the border.

“The White House is doing the right thing,” Giffords said. “Arizonans know that more boots on the ground means a safer and more secure border. Washington heard our message.”

Up until now, Giffords has been a regular critic of the administration for not doing enough on border security. In a National Public Radio interview last week, the Tucson Democrat said she was “very frustrated” with Obama’s lack of attention to her state’s border and said the administration “needs to step up.”