Can Republicans pull off a miracle tomorrow and keep control of the Senate? Veteran analyst Charlie Cook tells NBC’s Chuck Todd that they’ll come close — but control might come down to the presidential race. It comes down to nine key races, and Cook lines up at least five of them in the Democratic column, with two more too close to call:

The GOP currently holds the majority with 54 seats, meaning that Democrats need a net gain of four seats to win control of the upper chamber for the next two years if Hillary Clinton wins the presidency or a net gain of five should Donald Trump prevail.

Voters are indicating that they want a Congressional check on the president. While Clinton led by 4 points in the final pre-election NBC News/Wall Street Journal poll, 51 percent of likely voters said they were more likely to support a Republican congressional candidate who would serve as a check on a potential Clinton presidency. Just 40 percent said they would be more likely to support a Democratic congressional candidate who would support Clinton’s agenda. (Still, when voters were asked if they prefer a Congress led by Democrats or by Republicans, Clinton’s party retained an advantage, 47 percent to 44 percent.)

Last-minute cash infusions by the parties and by super PACs are keeping Senate races competitive and outcomes uncertain.

Cook has a long and solid track record on these calls, but he may be settling too soon on a couple of the races. In Wisconsin, Feingold has lost steam in polling near the end, and Republicans have a pretty good track record themselves on turnout over the last six years. The RCP average in Wisconsin has gone from seven or more points to less than three in a week. If one had to pick who has the advantage at this stage, it would be Feingold — but Johnson looks as though he has some momentum working in his favor, too. On the other hand, Nate Silver’s FiveThirtyEight puts the chances of a Johnson win at less than 20%, so Cook’s on pretty solid ground.

Ayotte’s chances in New Hampshire look much stronger, though. Hassan leads in a new UNH poll that came out today, but that’s the only non-partisan poll in the RCP aggregation in which she’s led in the general election. FiveThirtyEight actually gives Ayotte an extremely small edge over Hassan.

For that matter, Cook may be too quick to write off Joe Heck as well. RCP has it a toss-up, and so does Nate Silver. The early vote looks like a disaster for Donald Trump, but we’re not actually sure of that yet — and Heck might not get as damaged by it as Trump would anyway. If both of these two toss-ups break toward the GOP, suddenly the chances of holding the Senate look surprisingly good, especially given the long odds Republicans faced from the beginning in this cycle.

Townhall’s Matt Vespa and I previewed our Election Night coverage earlier today, and we gamed out the Senate as part of our analysis. Be sure to stay tuned on our Townhall Facebook page for more live coverage of the election and its results tomorrow.