As of 3 p.m. Friday, Sen. Bernie Sanders (I-Vt.) was entering his fifth hour of a “very long speech” outlining his opposition to President Barack Obama’s tax cut deal, and he was showing no signs of packing it up.

Sanders has emerged as the leading voice against Obama’s tax cut package, which the president crafted with Senate Minority Leader Mitch McConnell (R-Ky.). Sanders has sought to rally Democratic and Republican opposition to the bill, which is set for a procedural vote on Monday. The $900 billion package would extend for two years all of the Bush-era tax cuts and extend for 13 months unemployment insurance benefits.

Taking the floor at 10:15 Friday morning, Sanders began a marathon talkathon, the likes of which the Senate has not seen in years.

According to Sanders, his reason for giving the lengthy speech was simple — to “take a strong stand against this bill, and I intend to tell my colleagues and the nation exactly why I am in opposition to this bill.”

“You can call what I am doing today whatever you want, you can call it a filibuster, you can call it a very long speech. I’m not here to set any great records or to make a spectacle. I am simply here today to take as long as I can to explain to the American people the fact that we have got to do a lot better than this agreement provides,” Sanders added.

But while Sanders may not have intended to create a spectacle, the sight of the 69-year-old white-haired liberal conducting a Mr. Smith-style filibuster was clearly catching the public’s attention.

According to Sanders’ office, online viewers temporarily shut down the Senate’s servers Friday because of the speech, and his talkathon was listed as the No. 5 most talked-about topic on Twitter.

Meanwhile, Majority Leader Harry Reid (Nev.) and McConnell were reportedly in negotiations over whether Democrats would be allowed to offer amendments to the tax package next week. Details of the negotiations were unclear, and Republicans and the White House have remained adamant that no substantive changes will be allowed.