Make El Salvador and Honduras as safe as Guatemala?

On January 21st, twenty Senate Democrats petitioned the Obama administration to extend protection to an estimated 1.5 million undocumented immigrants from Honduras, El Salvador, and Guatemala currently residing in the United States.

The letter calls for additional resources to process undocumented migrants more fairly, an end to recent raids and the use of funds to contract with the Corrections Corporation of America to detain immigrant families, and that those eligible to stay be allowed to remain in the US until it is safe for them to return to their home countries. In general, I don’t really have a problem with any of the arguments made by the Senate Democrats. 
However, I’m just wondering whether US policy should treat all three countries the same. We do and we don’t depending upon the situation. The US pulled Peace Corps out of Honduras when its murder rate was over 90 per 100,000 and then out of El Salvador when its murder rate surpassed 100. We’ve limited volunteers to Guatemala but we’ve not pulled them out entirely.
Honduras’ rate is now down below 60 (if we can believe the numbers). Guatemala’s rate, on the other hand, has never been above 46 and now stands below 30 after several years of decreases. We can’t reduce security to a country’s murder rate but there’s a significant difference among rates of approximately 30 (Guatemala), 60 (Honduras) and 100 (El Salvador). 
Wouldn’t we be ecstatic (too strong?) if Honduras and El Salvador reduced their murder rates to that of Guatemala within the next five years? Obviously a lot depends on how the murder rate is decreased and what comes of other crimes (e.g., extortion) but is that a reasonable goal? I’m not sure rates in Costa Rica, Nicaragua, and Panama are reasonable goals.