This post has been updated below.

In these last days before the presidential election, Fox News has redefined its role as the "voice of the opposition" by turning the network into an extension of Republican presidential candidate Mitt Romney's campaign. A Media Matters review found that Fox's coverage of Romney campaign speeches in the past three days has neared a whopping hour and a half of total airtime.

By contrast, Fox's total coverage of President Obama's campaign speeches over the past three days lasted about 18 minutes, meaning the network has given Romney about 366 percent more airtime the week before the election to spread his message. Put simply, for every minute of airtime Obama received, Romney was afforded a little over four and a half minutes. In all, Fox's coverage of Romney speeches totaled an hour and 24 minutes.

MSNBC and CNN were both more balanced in their coverage. MSNBC gave Obama about 49 minutes in contrast to Romney's 42, while CNN provided Obama with 53 minutes as opposed to Romney's 42.*

On Saturday, Fox News kicked off its coverage with Romney's campaign rally in Portsmouth, New Hampshire, at 9 a.m. and cut away when he ended his remarks about 14 minutes later. It later aired his campaign speech in Dubuque, Iowa, for five minutes starting at 1:33 p.m.

Meanwhile, Fox News did not air Obama's first speech of the day in Mentor, Ohio, around noon, and only gave his rally in Milwaukee, Wisconsin, a passing mention at 4:31 p.m. In fact, Fox aired Obama's remarks for just 13 seconds before cutting away.

MSNBC covered Romney's speech in Dubuque for four minutes, and aired five minutes of Obama's comments in Mentor and two minutes of his Milwaukee remarks. CNN aired four minutes of Romney's Portsmouth comments and a minute of his speech in Dubuque. It also aired three minutes of Obama's remarks in Mentor and six minutes of his speech in Milwaukee.

Fox News' Friday coverage was almost as lopsided: Romney received 37 minutes of coverage for his campaign speeches, while Obama was afforded just 12 minutes.

Indeed, Fox aired Romney's entire 26-minute speech in West Allis, Wisconsin, live on Friday, but aired only three minutes of Obama's speech in Hilliard, Ohio.

Thursday's Fox coverage also followed this unbalanced trend: The network aired an entire 24-minute Romney speech live in Roanoke, Virginia, but cut away from Obama's remarks in Green Bay, Wisconsin, after just six minutes. Fox later aired five minutes of Romney's remarks in Doswell, Virginia, but did not cover any other Obama campaign stops.

UPDATE: In the 24 hours that followed, the disparity in Fox's coverage of the two candidates widened even further. Between 5 p.m. Saturday and 5 p.m. Sunday, Fox aired 84 minutes of Romney's speeches live, compared with nine minutes of airtime for Obama's speeches. Since Thursday, Fox has aired two hours and 48 minutes of Romney's speeches, as compared with 27 minutes of Obama's speeches.

On Saturday evening and during the day on Sunday, MSNBC aired 30 minutes of speeches from Obama and two minutes of speeches from Romney. CNN aired 13 minutes of Obama's speeches and 11 minutes of Romney's speeches.

The new totals:

*These totals reflect coverage up to 5 p.m. ET on November 4.

This post originally stated that Fox News gave Romney 80 percent more airtime than Obama, when in fact the truer figure is closer to 366 percent. Media Matters regrets the error.