Yes. As I said, it doesn't help that the most high-profile business of the Coalition has been reducing the defecit, and the Liberals agreed from the outset to allow the Conservative policy to dominate in this area.
Scotland and Ulster both seem to be running "two-and-two-halves" party systems (although for the former, that might no longer be the case), while Wales could very well be described as a "one-and-two-halves" system. Strange things, regional parliaments.The Liberal Democrats and their immediate ancestors haven't actually formed a government since at least the Second World War, and it's only since 2010 that they've had any real influence in policy-making. As such, one could definitely describe it as a 'two and a half' party system.
Urban Voters were always in the Democratic Block, AFAIK.
Urban voters are more left-wing, but not necessarily democratic. And by certain standards, the Republican party could be viewed as the more left-wing party until the rise of the New Deal coalition. Of course, you may be right.
The failure of the Republican government to deal with the problems of the Great Depression effectively led to many traditional Republican voters, specifically minority groups such as African-Americans, to vote for FDR in the 1932 presidential elections. While FDR actually did a fairly poor job of fixing the issues stemming from the Great Depression, he was very charismatic and had good publicity, enabling him to give the impression that he was doing a good job. This meant that the Republicans had lost their monopoly on the African-American vote, along with several other groups, none of them as large, permanently.
Once this happened, the Republicans were faced with either continuous electoral defeat or adapting to the new situation. While they were successful at first after WWII, this was largely because of the immense and bipartisan popularity of Eisenhower, who actually didn't care which of the two parties he ran for, so long as they gave him the power he requested. The Republicans offered him more than the Democrats, so he ran for them.
After Eisenhower retired, his Vice President, Richard Nixon, lost the election to JFK. Nixon owed much of his own popularity to his relationship with Eisenhower, and recognised that the Republican Party could only coast on Ike's coat-tails for so long. He developed the Southern Strategy, which was basically the idea of appealing to white Southerners, largely through racist campaigns and combatting the civil rights movement. It worked, and Nixon won two elections with the strategy. After Nixon, the pattern of today had largely been set, though it remains to be seen how it will change in the future.
The Progressive movement largely started within the Republican party. But competing within that party against the business interests encouraged a shift to the Democrats. A shift that was largely completed during FDR's time. That brought the Blacks almost entirely into the Democratic party, and the Northern Cities became a near Democratic lock from that point on. Southern whites conservatives began to migrate to the Republican party, with a big jump after the 60s, and another jump in the 80s, and pretty well completed during the 90s.
In the Civil War era, the Republican Party was formed out of the ashes of the Whigs as a Northern party opposed to the perceived growth of 'slave power' - the idea that slave-owning southerners wanted to expand slavery throughout the USA and the Americas and so increase their power over the free northerners. Whether this was actually happening is a matter for debate, but this meant that southerners generally thought that the Republicans were abolitionists, which they weren't until halfway through the Civil War. It says something that Abraham Lincoln didn't even appear on the ballot paper in most of the South in the 1861 election: he won entirely because the North had more people in it.
The South remained Democratic, generally, until the 1964 election, where white southerners voted Republican in protest at LBJ's Civil Rights Act, as Goldwater - one of the most conservative Republican nominees until that time - was campaigning against strong federal government, specifically the CRA. Nixon's strategy in 1968 specifically targeted white southerners angry at Civil Rights legislation, essentially changing the geographical positions of the two parties. In general, I suppose you could explain it by arguing that there is a Northern and a Southern party in US politics, and whichever party tends to support the general political outlook of the largest voting bloc in these areas will carry them. This is why the North, being generally more liberal than the South, generally supports the relatively liberal party, while the South, being generally more distrustful of federal government than the North (which I would argue is generally shorthand for racist), generally supports the Democrats.
I don't see that lasting for long TK.