There's a few points relating to this issue you didn't mention.

Rather than stating that immigration's an issue in the US at the moment, it's probably more truthful to say that the Obama administration is acting working to bring the illegals in.
They are certainly taking a pro-illegal immigrant position.
http://www.infowars.com/city-official-admits-us-border-patrol-fronting-cash-to-bus-illegals/
http://www.zerohedge.com/news/2014-11-13/obama-set-steamroll-republicans-give-5-million-illegal-immigrants-executive-amnesty-

Its been suggested that the democrats may be trying to buy the illegals votes.
http://www.zerohedge.com/news/2015-01-21/bill-proposed-allow-voting-without-us-citizenship
http://townhall.com/tipsheet/katiepavlich/2015/05/29/poll-majority-of-democrats-think-illegal-immigrants-should-vote-n2005563

Also, there's the Cloward and Piven strategy to deliberately collapse the economy by overwhelming the system with the costs of welfare.
http://www.zerohedge.com/news/2014-07-03/cloward-piven-strategy-being-used-destroy-america

Trump has brought the immigration issue to the attention of the corporate media ( who had been turning a blind eye to the issue under direction of the Whitehouse) as part of his Presidential campaign and has proposed building a wall across the Mexican border to stop the flow of illegals.
He's also stated that the Mexicans are deliberately pushing their criminal undesirables over the border just as Fidel Castro once did.

Immigration and Customs Enforcement (ICE) currently has a policy which has been referred to as 'Catch and Release", which basically gives the illegals who commit crimes diplomatic immunity.
http://www.washingtontimes.com/news/2014/mar/30/border-agents-catch-and-release-most-illegal-immig/?page=all

The immigration issue may also be a deliberate plan to drive down the costs of wages in the US.

Questions should be raised about the TPP and trade deals made in secret, The G20 (global economic governance) who also work in secret and their discussions and policies relating to employment and the UN Millenium Development Goals which advocates policies on refugee inflows and vaccines and promoting women.

Just comparing our governments policies to the UN Millennium Development Goals and you will see that our governments aren't really representing us as much as they are promoting UN policies.
http://www.un.org/millenniumgoals/

What happens when the illegals/refugees become so numerous that they start dictating the laws to the rest of us?
When government start to capitalise on their votes?

I don't think Obama wants to fix the issue.
It's just political posturing.. or theatre.
Politics is show business for ugly people.

Unauthorised arrivals ? I am not even sure you understand that means nothing. You are allowed to turn up and ask for asylum as a refugee. Is that what you mean ? People seeking asylum as a refugee ?

Economic migration happens around the world and in some places actually encouraged!

Would here be any harvesting of small crops in America without the illegal migrant element doing all the backbreaking picking/muck shoveling; and in most cases, for slave labour wages!

Israel imports new economic migrant settlers and into new settlements on patently purloined ground; ostensibly, just to keep the Jewish domination at the ballot box!?

That said the only way to prevent illegal economic migration is to fix the economies, where these desperately impoverished folks come from!

Which by the way may necessarily include surgically removing a self imposed dictator and his or her inner sanctum of murderous fellow travelers?

After which what is required is education outcomes; particularly for the native womenfolk and a spend a sprat to catch a mackerel, system of micro loans from small donated funds; where a single donated dollar does the work of thousands.

And a pool of money that can be used recycled and reused again and again until invariably exhausting; doing literal billions worth of work for mere millions!?

We want these empowered folk to be our newest trading partners; not our social service obligations!

And the only way to do that is keep hostile or overbearing governments and their invariably corrupt officials out of the loop; our sub launched cruise missiles are bigger and more accurate than your cruise missiles and we can send one through your front door if you interfere with our charity work in any way?

Meaning almost absolute reliance on fearless NGOs and not for profit grassroots organisations!

We might have to dig to find them, but they're there! And Gandhi showed how a nation can and does defy dictators!?

And a better option than prison camp like, detention centres and routinely wasted billions?
Rhrosty.

Hi Valley guy

Unauthorised migrants have no legal right to live in the USA, but either enter illegally or overstay their visas. Most do not claim to seek asylum from persecution, but are just hoping for a better life. As I understand it they don’t get to claim unemployment or welfare benefits and most are looking for work.

Illegal migration has a long history in the USA, and is generally viewed less negatively than here, perhaps in part because they are not a major welfare burden and are often perceived as hard-working and enterprising.

I remember being shocked and amused some years ago travelling in southern California by this roadside warning sign, "wetbacks crossing"

https://www.google.com.au/search?q=wetbacks+crossing&num=100&safe=off&tbm=isch&imgil=nYKBQ7QskUI4rM%253A%253BhnpbAiisXPqoLM%253Bhttp%25253A%25252F%25252Fs159.photobucket.com%25252Fuser%25252Fkrunkest_bytch_eva%25252Fmedia%25252FWETBACKS.gif.html&source=iu&pf=m&fir=nYKBQ7QskUI4rM%253A%252ChnpbAiisXPqoLM%252C_&biw=1280&bih=827&usg=__Qwnf94MRZxX6xVRcHXH7nbLeJ9o%3D&ved=0CCkQyjdqFQoTCJqQso2K_cYCFUappgodW7MGOw&ei=KhG3VZrTFcbSmgXb5prYAw#imgrc=HBVrdTsRuwT2dM%3A&usg=__Qwnf94MRZxX6xVRcHXH7nbLeJ9o%3D