President Obama is asking Congress for billions to handle a border crisis, but that doesn't mean he'll get it.

The administration won't get the $3.7 billion unless Republicans in the House and Senate go along with the request, but there are several reasons that may not happen.

Here are five reasons why:

Republicans want more of the money to go to deportations

Almost half of Obama's $3.7 billion request would go to the Department of Health and Human Services to provide aid to the illegal arrivals. But some Republicans want more money to be spent on deportations and beefing up border security. House Speaker John Boehner, R-Ohio, has called for the National Guard to be deployed to the border. His spokesman noted Tuesday that Obama's proposal does not include Boehner's suggestion. Other Republicans want the supplemental money to include more spending on border security to address the larger issue of illegal immigration. “I can't imagine we would proceed through this process without reforming some of the obvious incentives for illegal entries,” Sen. Jeff Sessions, R-Ala., said.

The request doesn't include a measure for speedier deportations

Republicans are livid the president has flip flopped on his initial plan to request greater authority to deport the thousands of children illegally entering Texas in recent weeks. The children have been allowed to stay under a 2008 law barring the speedy deportation of minors to countries other than Mexico or Canada. Republicans will likely insist on changing the law to lift the ban. “I don't think it can pass without it,” Sen. John McCain, R-Ariz., said. Democrats and Obama, however, may oppose the provision because they are facing strong pressure from immigrant advocacy groups who want the children to be granted refugee status.

Both parties can't agree on how to offset the cost

Republicans will insist on finding cuts elsewhere in the budget to pay for the supplemental, particularly if less than half the money will be dedicated toward improved border security. Democrats will likely oppose Republicans-favored cuts. “We should find other areas in the government we can cut,” Sen. Ron Johnson, R-Wis., said. “The president is very good at throwing money at problems and not solving them.”

The Senate is gridlocked already

Senate Republicans and Democrats are at war over legislative procedure, which has stalled even bipartisan bills. The GOP wants the Democratic majority to grant them amendments but Senate Majority Leader Harry Reid, D-Nev., has blocked them at every turn. Senators are already talking about wanting to amend the border funding measure, which could lead to a standoff with Reid and more gridlock.

Conservatives have just enough power to block the bill

The House is expected to take up the spending bill before the Senate, but the House Republican conference includes dozens of far right conservatives who will not only oppose the cost of the bill, but will insist on attaching spending cuts as well as deportation and border security provisions Senate Democrats won't like. In the Senate, conservatives could could block the bill, which would likely require at least five Republicans to overcome a filibuster. The conservative watchdog group, Heritage Action for America has called the president's proposal a "nonstarter," and many in the GOP feel the same way. “Let the president come out and say that people are not going to be rewarded for breaking the law and coming here,” Sen. James Inhofe, R-Okla., said, in response to the spending proposal. “That is what the president needs to do and pouring money on it won't help.”