Washington has never been more partisan, right? Or is that common lament simply a trick of nostalgia? A look at the numbers reveals that the problem is not, it turns out, all in our heads: over the last four decades, Congressional polarization has steadily increased.

Since 1947, Americans for Democratic Action, a liberal advocacy group, has tracked the political positions of each Senate and House member, scoring how they voted each year on 20 key bills covering a variety of social and economic issues. (Many groups from across the political spectrum calculate lawmakers' dedication to various ideologies and causes. The Signal is merely using this group's data because it is collected over many years and is based on the controversial votes that reveal the fault lines in the House and Senate.)

In the graph below, the colored bands indicate where the middle 50% of each party ranks on the ADA's scale. A narrower band means the heart of the party usually votes in tandem; a wider band shows that lawmakers feel a certain license to vote against the party on more occasions.
Polarization in Congress by Sharad Goel

Mitt Romney coasted to victory in the Nevada caucuses in 2008 with over 50 percent of the vote, more than his six opponents combined. He's poised to make it two straight on Saturday. Newt Gingrich is heavily favored to take second place with about 80 percent likelihood to Ron Paul's 20 percent chance, according to the prediction markets.

The first thing that most people associate with Nevada is Vegas. About 70 percent of the population lives in Clark County, home to Las Vegas and the surrounding metro area. In 2008, Barack Obama won the county by nearly 20 percentage points. But Nevada's primary contest is closed, meaning only registered Republicans can vote. In 2008, about 50 percent of the Republican caucus goers were from outside of Clark County. And, most importantly for Romney, roughly 1 in 5 were Mormons, who voted 9 in 10 for Romney.

Mormons are 74 percent Republican and they have proven extremely loyal in voting for Romney, who is a leader in the Church. Thus, even relatively

Almost immediately after polls closed at 8 p.m. ET, the major networks called the state of Florida for Mitt Romney. The markets were extremely confident in this outcome, as we noted yesterday, so there was no major movement in the overall odds for the nomination; Romney crept up about two percentage points to an 88 percent chance of being the Republican nominee for president.

The twittersphere erupted immediately, referencing the former Massachusetts governor at a rate of nearly 500 tweets per minute--for all of 10 minutes. (That's not necessarily abrupt, as far as Twitter goes.) Queries about Romney on Yahoo! Search also briefly spiked to about 10 times their usual rate. Romney enjoyed a second, lesser, spike as he delivered his victory speech. (Ron Paul, as usual, received the highest online interest among all the candidates during the Florida speeches.)

Our measure of Twitter sentiment found that, while the buzz around Romney was mostly negative at 8 p.m. as his victory in the