2. I did mean Harris country - that was a typo, and indeed it is true that in '06 no Republican won by more then 35,000 except for Poe - and he represents the northern suburbs of Houston, not the part that most Katrina evacuees are living in. Culberson, McCaul and Paul were all at or below 60% in '06 without the Katrina refugee vote. Even if a significant fraction of Katrina refugees in Houston begin to vote in the future, that will be a factor in some of the other Republican seats around Harris; Perhaps not enough to swing the seats, but certainly enough to force Republicans to divert resources.
You do realize that there are very few (if any) Katrina refugees in McCaul's TX-10 (northwest exurban Harris County), Paul's TX-14 (Brazoria County is not where they settled, nor is the still rural part of Fort Bend that is Paul's CD, neither his part of Galveston county which is highly suburban).
Paul's numbers, I suspect, were b/c of his anti-Iraq stuff (which would not go over well in that CD, even in 2006). McCaul actually had an opponent in 2006, unlike 2004, and his poor performance was actually in the rural areas of that CD (interestingly enough).
Some Katrina refugees have probably settled in Culberson's TX-07, but I am pretty sure that CD is carefully designed in Southwest Houston to take in mainly Bellaire (suburban) and Meyerland (Jewish) and doesn't take in that much black/Hispanic shifting area along Richmond Avenue. The area inside 610 is more moderate Republican/Independent than anything - those areas in this country acted more anti-Republican than any others in 2006 (Texas was not excluded). The other areas outside 610 are pretty hyper-Republican suburbs of Houston. And truthfully, local Republican candidates in Texas suffered about a generic 5% shift against them statewide in all the races I've studied. Strangely enough, this shift seemed to be the smallest in statewide elected offices that were not national (excluding Governor, of course).
Most (if not all) of the Katrina refugees settled in southwest Harris County - b/c that's where the city placed them. Generally, they placed them in the large apartment complexes and condos that populate the area around Fondren, Gessner and Chimney Rock avenues - that were actually white areas back in the 1980s, started becoming black (w/some Hispanic) starting in the early-to-mid 1990s and were generally black by the early part of this decade.
This area is all within Al Green's very safely Democratic TX-09. If area of these refugees were in any Republican districts, it would probably be TX-22 (or as mentioned earlier TX-07 or Sheila Jacson Lee's CD - not GOP), but they would be in only the Fort Bend Cty parts of that CD (and the numbers probably weren't that great), not the Harris County parts - which are mainly suburban white.