system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What's going on with the DHS funding and why can't they come to an agreement?
gpt
Because the DHS department is the department that funds immigration-related activities.  

Not too long ago, President Obama issued an executive order of moderately debatable constitutionality that would use DHS to quasi-legalize a large number of heretofore "illegal" immigrants, which republicans are opposed to.

Depending on your political bent, Obama's action was either a totally overdue and legitimate extension of Presidential authority to fill a much needed gap and the technical legal argument is much ado about nothing,  or it was an abhorrent sacrelige against the Constitution and all other things righteous and holy.

Congress cannot directly stop Obama's executive order for 2 reasons:  (1) Because democrats hold more than 40 seats in the seante, Republicans cannot overcome a filibuster,   and (2) Because democrats hold more than 33 seats in the senate, republicans cannot overcome an inevitable Presidential veto, even if the Democrats don't filibuster.

However, republicans' ace in the hole in all this is that they have the "power of the purse", meaning they decide what gets funded and what doesn't.  It's in the constitution specifically;  the House of Representatives must initiate all spending bills.  So their denying funding to the DHS is a backdoor way to fight the executive order where Republicans have more leverage.  No money for DHS = Obama can't implement his executive order allowing immigration.

Alas, this means that the whole rest of the DHS and its workers are caught in the crossfire while Obama and Republicans wrangle it out.