It comes down to a point where Pence may be counting the electoral college votes in the House of Representatives with all senators and House memebers present and may say "there are two competing slates of electors, one slate signed by the democrat governors and one slate with power vested in it by the state legislature, therefore, I cannot count these".

"...Then, Nancy Pelosi rises, demanding to speak. (Under 3 U.S.C. § 16, she sits “immediately upon [the Senate president’s] left.”). She announces that the joint meeting of two chambers is over, or at least suspended, unless and until Mike Pence is prepared to change his ruling and accept the electoral votes from Pennsylvania bearing the governor’s signature. Absent that, the Senators are no longer welcome in the House chamber. When Pence insists that Pelosi has no authority to suspend the proceedings in this way, Pelosi declares that she will call upon the sergeant-at-arms of the House of Representatives to forcibly remove the senators from the House chamber unless the senators leave voluntarily. In order to avoid that spectacle, and in the hope that Republicans will eventually triumph after cooler heads prevail, Pence reluctantly agrees to lead the Senators out of the House chamber.

With the House now alone in its own chamber, and Speaker Pelosi presiding, the House (in a party-line vote) passes a resolution stating that the joint proceeding under the Twelfth Amendment and 3 U.S.C. § 15 is hereby suspended unless and until Vice President Pence publicly announces that he is prepared to count the electoral votes from Pennsylvania as certified by the governor. Until then the House has ordered its sergeant-at-arms to bar the reappearance of Pence or any other Senator in the House chamber. Pelosi, however, does not go so far as to bar Republican members of the House from leaving the chamber, and they do.

With Pelosi and the Democrats refusing to budge, Pence and the Republicans decide they need to do what they can to continue the counting of electoral votes, even if they cannot return to the House chamber. Consequently, Pence invites senators and representatives to crowd into the Senate’s chamber for this purpose. Only Republican senators and representatives show up, except for one designated Democratic Senator to protest the purported continuation of the proceedings as unlawful under 3 U.S.C. § 15 and the Twelfth Amendment.

Among other objections, this Democratic senator points out that 3 U.S.C. § 15 specifically requires that there be two “tellers” from each chamber to participate in the opening and counting of electoral votes from the states: “said tellers, having then read the [the submission of electoral votes from the states] in the presence and hearing of the two Houses, shall make a list of the votes as they shall appear from the said certificates.”62 Because the House of Representatives is no longer participating, as declared in its formal resolution, there no longer are two tellers from the House to perform this statutory function. Because the two House tellers must have been “previously appointed” by the House, according to the explicit terms of 3 U.S.C. § 15, there is no authority vested in the President of the Senate or elsewhere to appoint substitute tellers from the House. In other words, this Democrat asserts, there can be no continuation of the joint proceeding under 3 U.S.C. § 15 without the institutional participation of the House, and the House has resolved that institutionally it will not invite the Senate back to its chambers for the continuation of the joint proceeding unless and until the President of the Senate announces that the electoral votes bearing the certificate of Pennsylvania’s governor will be counted, per the terms of 3 U.S.C. § 15. Notwithstanding this objection from the Democratic senator, Pence purports to proceed with the counting of electoral votes..."

There would then be two competing claims for the presidency: the first being that Nancy Pelosi becomes acting president until the issue is sorted and the 'correct' votes (governor-signed) are counted, the second being the result that Pence declares Trump the winner after counting the state-legislature assigned electoral votes.

The difference between our scenario and their scenario is that pence may refuse to count the votes. The question is then whether the senate chamber forces him to count the votes (looking at you Mitch and the potential for RINOs to go against Pence here), or whether Pence manages to count. Either way, this could get really fucking messy.

I'm sure we can count on Romney.