The problem with the US government is a tragedy of the commons (ie the district-by-district and state-by-state pork barrelling).
The original intent of the Founding Fathers and the view held by libertarians and traditional conservatives (rather than the neoconservatives and religious conservatives that dominate today) is one of limited Federal government for specifically this reason. A minimal government is one not worth buying. A big and intrusive government is one totally worth buying.
Representatives and Senators raise so much money to get elected because the payoff is huge. Both in terms of direct power and the indirect financial reward (many become lobbyists for huge incomes). Lobbying isn't the problem; it's a symptom (of government being worth buying).
Davy Crockett [1] is oft-quoted on this subject.
This is why I found the "living document" "ideology" so subversive. I say "ideology" because I find myself agreeing with Justice Scalia that it is no ideology at all. The Constitution doesn't say whatever you want it to say. It says what it says. If you want pass laws or amendments otherwise well there are processes for that and it's the job of the legislative not the judicial branch to create new law.
The road to hell is paved with good intentions.
I think the bigger problem in US politics is that the country itself is divided and so many people think the means justify the ends.
Take how elections are organized. It's clear that some states seek to suppress traditionally Democratic votes in the names of striking convicted felons off the electoral rolls. Other states try and manipulate the vote by the density of polling places and the hours they are open.
I compare this to Australia, which holds elections on a Saturday, and those elections are organized by the AEC (Australian Electoral Commission). Voting is mandatory not optional and the duty of the AEC is to ensure that everyone has ample opportunity to vote. It seems that some combination of cultural factors, the smaller size of the Australian population and mandatory voting has made this a largely nonpartisan endeavour and voting has only ever taken me 10 minutes. On Saturdays they just set up in schools and other public spaces.
Redistricting too is a hugely political issue but the big problem here is that voting patterns are so predictable that you can buy maps telling you how specific city blocks vote.
Half the country votes. Of that half, 40% always vote Republican. 40% always vote Democrat. The remaining 20% (meaning 10% of the population) actually determinate the outcome of the election. The largest electoral victories in US history (Nixon in '72 and Reagan in '84) each only captured ~60% of the populate vote.
You see the effects of this on Congress with reelection rates [2]. Being a Representative is now a career and that (IMHO) is a problem.
"Winning" on issues for many has trumped the rule of law and the Republic itself (again, IMHO) and that more than anything is the most dangerous thing.